Showing papers in "Journal of Helminthology in 2011"

In vitro activity of Cameroonian and Ghanaian medicinal plants on parasitic (Onchocerca ochengi) and free-living (Caenorhabditis elegans) nematodes

Abstract: Ethanolic and aqueous extracts of selected medicinal plants from Cameroon and Ghana were assessed for their in vitro anthelmintic activity by using the bovine filarial parasite Onchocerca ochengi and the free living nematode Caenorhabditis elegans, a model organism for research on nematode parasites. Worms were incubated in the presence of different concentrations of extracts and inhibitory effects were monitored at different time points. Among the extracts used in this study, ethanolic extracts of Anogeissus leiocarpus, Khaya senegalensis, Euphorbia hirta and aqueous extracts from Annona senegalensis and Parquetina nigrescens affected the growth and survival of C. elegans and O. ochengi significantly. The mortality was concentration dependent with an LC50 ranging between 0.38 and 4.00 mg/ml for C. elegans (after 72 h) and between 0.08 and 0.55 mg/ml for O. ochengi after a 24 h incubation time. Preliminary phytochemical screenings on these extracts revealed the presence of flavonoids, alkaloids, saponins, carbohydrates and tannins in the extracts. Accordingly, application of A. leiocarpus, K. senegalensis, E. hirta and A. senegalensis extracts could provide alternatives in the control of helminthic infections.

An abattoir-based study on the prevalence and economic losses due to cystic echinococcosis in slaughtered herbivores in Ahwaz, south-western Iran.

Abstract: A 10-year (1998-2008) retrospective study was carried out to investigate the prevalence and long-term trend of hydatid disease in slaughtered herbivores in the large complex abattoir of Ahwaz (the capital of Khuzestan province, south-western Iran). A total of 3,583,417 animals including 2,815,982 sheep, 427,790 goats and 339,645 cattle were inspected macroscopically for hydatid cysts in the 10-year period, and overall 155,555 (4.24%) livers and 228,172 (6.37%) lungs were condemned. Cystic echinococcosis (CE) was responsible for 36.08% and 48.04% of total liver and lung condemnations, respectively. The prevalence of pulmonary hydatid disease in sheep, goats and cattle was 2.22, 5.43 and 6.99%, respectively; on the other hand, the prevalence of hepatic hydatid disease for those animals was 1.26, 2.57 and 2.80%, respectively. Data showed an overall downward long-term trend for CE in all livestock slaughtered during the study period (P < 0.01). Lung condemnation due to CE was significantly more common than liver condemnation for each animal separately (P < 0.001). The prevalence of liver and lung hydatidosis in sheep was significantly lower than that in other livestock (P < 0.001). The prevalence of hydatid disease recovered from the sheep, cattle and goats varied in different seasons, but there was no statistical difference between various seasons. The odds ratio of lung and liver condemnations due to hydatidosis showed a slightly different pattern in some years; however, the overall declining trend was still observed. The total annual economic loss incurred due to hydatidosis in all ruminants slaughtered at Ahwaz municipal abattoir was estimated to be US$459,659.6, based on the market prices in the year 2008. This number corresponds to a loss of US$300,620.4 for cattle, US$123,490.0 for sheep and US$35,549.2 for goats. The current results provide baseline data for the future monitoring of this potentially important disease in the region, and also suggest that a thorough investigation leading to a disease control strategy is required to reduce the economic and public health consequences of CE.

Helminth infections of wild boars (Sus scrofa) in the Bursa province of Turkey

Abstract: The present study aimed to investigate the status of helminth infections in wild boars in the Bursa province of Turkey. For this purpose, during 2007 – 2008, 27 wild boars were necropsied and examined for helminths. Individual samples of tongue and diaphragm from 27 necropsied wild boars and an additional 22 tongue and diaphragm samples provided by hunters were examined by trichinoscopy and artificial digestion for Trichinella spp. larvae. Twenty animals (74%) were identified as being infected with at least one helminth species. Twelve species of helminths were detected, with the following prevalence rates: Metastrongylus apri (59%), Metastrongylus salmi (52%), Metastrongylus pudendotectus (52%), Dicrocoelium dendriticum (33%), Globocephalus urosubulatus (22%), Macracanthorhynchus hirudinaceus (19%), Gongylonema pulchrum (11%), Physocephalus sexalatus (7%), Trichuris suis (7%), Ascarops strongylina (4%), Hyostrongylus rubidus (4%) and Taenia hydatigena larvae (4%). Generally, lungworms were the predominant helminths. The highest mean abundance was observed for M. pudendotectus, and the lowest was determined for T. hydatigena larvae. Significant differences in the prevalence and intensity were found for D. dendriticum with respect to host age and sex, respectively. The mean intensity of M. pudendotectus was significantly influenced by the sex and age of the wild boars. This study is the first report describing the presence of M. salmi, M. pudendotectus, D. dendriticum, G. urosubulatus, M. hirudinaceus, P. sexalatus, A. strongylina and H. rubidus in wild boars in Turkey. All analysed muscle samples were negative for Trichinella spp. larvae.

Molluscicidal and ovicidal activities of plant extracts of the Piperaceae on Biomphalaria glabrata (Say, 1818).

Abstract: Schistosomiasis is a tropical disease caused by Schistosoma and occurs in 54 countries, mainly in South America, the Caribbean region, Africa and the eastern Mediterranean. Currently, 5 to 6 million Brazilian people are infected and 30,000 are under infection risk. Typical of poor regions, this disease is associated with the lack of basic sanitation and very frequently to the use of contaminated water in agriculture, housework and leisure. One of the most efficient methods of controlling the disease is application of molluscicides to eliminate or to reduce the population of the intermediate host snail Biomphalaria glabrata. Studies on molluscicidal activity of plant extracts have been stimulated by issues such as environmental preservation, high cost and recurrent resistance of snails to synthetic molluscicides. The aim of this study was to determine the molluscicide action of extracts from Piperaceae species on adult and embryonic stages of B. glabrata. Fifteen extracts from 13 Piperaceae species were obtained from stems, leaves and roots. Toxicity of extracts was evaluated against snails at two different concentrations (500 and 100 ppm) and those causing 100% mortality at 100 ppm concentration were selected to obtain the LC 90 (lethal concentration of 90% mortality). Piper aduncum, P. crassinervium, P. cuyabanum, P. diospyrifolium and P. hostmannianum gave 100% mortality of adult snails at concentrations ranging from 10 to 60 ppm. These extracts were also assayed on embryonic stages of B. glabrata and those from P. cuyabanum and P. hostmannianum showed 100% ovicidal action at 20 ppm.

Variation in the helminth community structure of three sympatric sigmodontine rodents from the coastal Atlantic Forest of Rio de Janeiro, Brazil

Abstract: One hundred and eighty specimens of sigmodontine rodents living in sympatric conditions were collected in the Atlantic Forest in the state of Rio de Janeiro, Brazil (25 Akodon cursor, 98 Akodon montensis and 57 Oligoryzomys nigripes) to examine whether the helminth structure and component communities can be characterized among these three closely related rodents. The parasite species richness was 9 in A. cursor, 12 in A. montensis and 12 in O. nigripes. Five species were common to the three rodent species, and eight were common to A. cursor and A. montensis. The trichostrongylids - Stilestrongylus eta in A. cursor, S. aculeata in A. montensis and S. lanfrediae in O. nigripes - were the species with highest dominance frequency and determined the characterization of individual community structures. The prevalence and abundance of concurrent helminth species among rodents were significantly different. Canonical multivariate analysis demonstrated a similar helminth community structure between A. cursor and A. montensis but a high discrepancy between Akodon spp. and O. nigripes. Thus, the data indicated that small rodents such as A. cursor, A. montenis and O. nigripes that are sympatric and phylogenetically related have a different community structure, but similar component community, suggesting the role of helminth specificity and the hosts' habitats as determinants in structuring their helminth communities.

Population dynamics and spatial distribution of monogeneans on the gills of Oreochromis mossambicus (Peters, 1852) from two lakes of the Limpopo River System, South Africa.

Abstract: (Accepted 18 April 2010; First Published Online 27 July 2010)AbstractAn investigation was conducted into the parasitic infection of an indigenouscichlid, Oreochromis mossambicus, collected seasonally from the Nwanedi-Luphephe dams of the Limpopo River System from July 2007 to April 2009.Of 157 host specimens examined, 115 (73.25%) were infected by at least one gillparasite. In all, 1565 monogenean specimens were collected, belonging to fivedifferent species and two genera: Cichlidogyrus (C. halli, C. sclerosus, C. tilapiae andC. dossoui) and Scutogyrus (S. longicornis). Infracommunities were poor, with only27 (17.20%) hosts harbouring four of the five species observed. Cichlidogyrus halliwas the dominant species, with a prevalence of 73.25%. Prevalence values foreach of the other four species were less than 50%. The mean intensities for each ofthe five species were low (,8 parasites/host). The parasite abundance andintensity levels were not influenced by either the sex or the size of the host.The abundance of all parasite species except for S. longicornis exhibited seasonalfluctuations, reaching peaks in winter and summer. The spatial distribution ofeach parasite was studied on different regions of the gill, and positiveassociations among some species were revealed.Introduction

The prevalence and abundance of helminth parasites in stray dogs from the city of Queretaro in central Mexico

Abstract: The prevalence of helminth species in stray dogs, from the capital city of the state of Queretaro, was evaluated. A total of 378 dogs were captured and examined for the presence of helminths from January to December 2008. The results showed that 275 (72.8%) of examined dogs were infected with one or more helminth species. Single infections were observed in 139 (50.5%) of infected dogs and 136 (49.5%) harboured mixed infections. Out of the 378 dogs examined, 208 (55.2%) presented nematodes and 182 (48.1%) cestodes. The prevalences (confidence interval) and mean intensities of infection ( ± SD) of nematodes and cestodes encountered were: Ancylostoma caninum 42.9% (37.9–47.8) and 22.1 ( ± 34.3); Toxocara canis 15.1% (11.8–19.0) and 8.3 ( ± 15.0); Spirocerca lupi 4.5% (2.7–7.1) and 3.9 ( ± 4.8); Toxascaris leonina 2.3% (1.1–4.5) and 4.8 ( ± 3.5); Physaloptera praeputialis 1.9% (0.8–3.8) and 9.7 ( ± 14.9); Dirofilaria immitis 1.3% (0.4–3.1) and 5.6 ( ± 2.1); Oslerus osleri 0.3% (0.0–1.6) and 5 ( ± 0.0); Dipylidium caninum 44.9% (40.0–50.0) and 18.1 ( ± 27.7); Taenia spp. 6.9% (4.7–9.9) and 6.9 ( ± 7.1). There were no significant differences in prevalences observed either between female (68.5%) and male (76.8%) or between young (70.6%) and adult (74.2%) animals. No differences were observed in the ANOVA test for the mean intensity of infection of any of the parasites (P>0.05).

Epidemiology of intestinal helminth parasites in stray dogs from markets in south-eastern Nigeria.

Abstract: A survey of gastrointestinal helminth parasites of stray dogs (Canis familiaris) was conducted at Obollo-Afor and Ekwulobia markets, in Enugu and Anambra States, south-eastern Nigeria, respectively, to determine the patterns of infection among dogs in different parts of south-eastern Nigeria. Faecal samples collected, using long forceps, from every dog encountered in the markets between June 2007 and December 2008 were analysed by the Kato–Katz technique. Out of 413 dogs examined in both markets, 217 (52.6%) were infected with at least one of five parasites (Toxocara spp., Dipylidium caninum, Ancylostoma caninum, Taenia spp. and Trichuris vulpis). Overall faecal egg intensity of infection was 49.9 ± 58.7 eggs/g (epg). The prevalence of infection was comparable between the markets and between the male and female dogs, but varied significantly (P < 0.05) by age, decreasing from 78.9% in pups to 36.0% in adult dogs. The mean intensity pattern was similar to that of prevalence, decreasing from 86.7 ± 63.0 epg in pups to 22.1 ± 34.4 in adults. The most important individual parasite infection was Ancylostoma spp. (39.2%; 30.0 ± 41.2 epg) while T. vulpis was the least important (1.9%; 0.7 ± 5.4 epg). Generally, prevalence and intensity patterns of each parasite were also comparable between the markets and between sexes, but significantly (P < 0.05) age-dependent. The implications of these findings to public health in Nigeria and other endemic countries are discussed in relation to options for cost-effective control design and implementation.

Evaluation of crude hydatid cyst fluid antigens for the serological diagnosis of hydatidosis in cattle.

Abstract: Echinococcosis is a zoonotic infection caused by adult or larval (metacestode) stages of cestodes belonging to the genus Echinococcus. The purpose of this study was to evaluate the antigenic ability of hydatid cyst fluid antigen for the diagnosis of hydatidosis in cattle using enzyme-linked immunosorbent assay (ELISA) and indirect haemagglutination test (IHA). The source of the antigens for the serological tests was fertile crude cyst fluids collected from naturally infected sheep at the Addis Ababa abattoir. A total of 502 sera were collected from 329 uninfected cattle and 173 hydatid-infected cattle which were confirmed by post-mortem examination. Most cysts were sterile and multiple organ infection predominated. Of 173 infected cattle, 166 (96.0%; confidence interval (CI) 91.8-98.4) were positive using ELISA while 7 (4.0%) were negative. Of 329 sera from uninfected cattle, 274 (83.3%; CI 78.8-87.2) were found to be negative and the remaining 55 (16.7%) were positive by ELISA. Of 173 infected cattle, 151 (87.3%; CI 81.4-91.9) were positive and 22 (12.7%) were negative by IHA. Of 329 negative sera tested using IHA, 266 (80.9%; CI 76.2-85.0) were negative and the remaining 63 (19.1%) were positive. The false positive and negative values of ELISA were 4.0 and 16.7%, respectively, and the corresponding values of IHA were 12.7 and 19.1%. The sensitivity and diagnostic efficiency of IHA were 87.2 and 83.6%, respectively. Crude hydatid cyst fluid antigen seems to have reasonable antigenic properties and hence could be employed for epidemiological surveillance of cattle hydatidosis.

A combination of two Brugia malayi filarial vaccine candidate antigens (BmALT-2 and BmVAH) enhances immune responses and protection in jirds

Abstract: In this study filarial recombinant protein or DNA vaccine constructs encoding BmALT-2 and BmVAH as single or as cocktail antigens were evaluated. Male jirds were immunized intramuscularly with DNA vaccine constructs or were immunized intraperitoneally with protein vaccine. The single and bicistronic DNA constructs induced substantial interferon-γ responses in spleen cells; antigen-specific responses were higher following immunization with the bicistronic cocktail construct and evoked a significant protective response of 57% in jirds challenged with Brugia malayi that was similar in the antibody-dependent cellular cytotoxicity (ADCC) assay and micropore chamber experiment. The cocktail protein vaccines induced a mixture of IgG2a (Th1) and IgG1 (Th2) responses with 80% protective response when challenged with B. malayi infective larvae. However, the single protein vaccine rALT-2 induced Th2 (IgG1/IgG3) with a 70% protective response and rVAH induced Th1 (IgG2a) with a lower proliferative response with 60% protection following challenge with B. malayi infective larvae. These results suggest that filarial cocktail protein vaccines are able to elicit substantial immune and protective responses when compared with single antigen vaccination in suitably vaccinated jirds.

Molecular approaches to the identification of Bulinus species in south-west Nigeria and observations on natural snail infections with schistosomes.

Abstract: The current study considers the distribution of a small sample of 138 Bulinus snails, across 28 localities within eight Nigerian states. Snails were identified using a combination of molecular methods involving both DNA sequencing of a partial cytochrome oxidase subunit 1 (cox1) fragment and restriction profiles obtained from ribosomal internal transcribed spacer (its) amplicons. The results showed that the majority of Bulinus samples tested belonged to the species Bulinus truncatus while only two were Bulinus globosus. The use of RsaI restriction endonuclease to cleave the ribosomal its of Bulinus, as a method of species identification, was adopted for the majority of samples, this being a quicker and cheaper method better suited to small laboratory environments. Polymerase chain reaction (PCR) amplification of the schistosome Dra1 repeat within each of the collected Bulinus samples was employed to determine the extent and distribution of infected snails within the sample areas. Successful amplification of the Dra1 repeat demonstrated that 29.7% of snails were infected with schistosomes. Sequencing of the partial schistosome its from a small subset of snail samples suggested that some snails were either penetrated by both Schistosoma haematobium and Schistosoma bovis miracidia or hybrid miracidia formed from the two species.

Trypanorhynch cestodes of teleost fish from the Persian Gulf, Iran.

Abstract: A total of 299 fish belonging to ten teleost species were studied in Iranian waters at the north-eastern coast of the Persian Gulf for larval trypanorhynch cestode infection. The following trypanorhynch species were identified: Callitetrarhynchus gracilis Pintner, 1931, Pseudogilquinia thomasi (Palm, 2000), Pterobothrium lesteri Campbell and Beveridge, 1996 and Pseudolacistorhynchus shipleyi (Southwell, 1929). The most abundant parasite was C. gracilis which was isolated from seven teleost species. The highest prevalence (62.9%) and dominance (0.98) were demonstrated for P. thomasi with a maximum intensity of 22 in Indian halibut Psettodes erumei. Collections of P. lesteri and P. shipleyi from the Persian Gulf represent new locality records, thus extending the known range of distribution for both species. Four new host records are established. The recorded combination of trypanorhynch species and the established host range correspond to other regions, such as off the Brazilian coast. In terms of species distribution, the north-western part of the Indian Ocean, together with the Gulf of Bengal and the Indonesian archipelago, share the same species, resulting from connected water bodies. All trypanorhynch species were isolated from the body cavity, except for P. thomasi which was recorded from the musculature of P. erumei. Relatively high intensities of infection in P. erumei may be of public health concern in the region, necessitating the consumption of well-cooked fish products.

First report of larval stages of Fasciola hepatica in a wild population of Pseudosuccinea columella from Cuba and the Caribbean.

Abstract: A wild population of the lymnaeid snail Pseudosuccinea columella infected by larval stages of Fasciola hepatica was discovered in the Pinar del Rio Province, Cuba. One of 100 snails was infected in a rice culture field. This is the first time this species has been found acting as intermediate host of F. hepatica under natural conditions, not only for Cuba but also for the Caribbean area.

Optimizing protease production from an isolate of the nematophagous fungus Duddingtonia flagrans using response surface methodology and its larvicidal activity on horse cyathostomins.

Abstract: Protease production from Duddingtonia flagrans (isolate AC001) was optimized and the larvicidal activity of the enzymatic extract was evaluated on infective horse cyathostomin larvae (L3). Duddingtonia flagrans was grown in liquid medium with eight different variables: glucose, casein, bibasic potassium phosphate (K2HPO4), magnesium sulphate (MgSO4), zinc sulphate (ZnSO4), ferrous sulphate (FeSO4), copper sulphate (CuSO4) and temperature. The Plackett-Burman analysis showed a significant influence of MgSO4, CuSO4 and casein (P < 0.05) on protease production by D. flagrans in liquid medium. Central composite design indicated that the highest proteolytic activity was 39.56 U/ml as a function of the concentrations of casein (18.409 g/l), MgSO4 (0.10 g/l) and CuSO4 (0.50 mg/l). A significant difference (P < 0.01) was found for the larval number between the treated and control groups at the end of the experiment. A reduction of 95.46% in the number of free-living larvae was found in the treated group compared with the control. The results of this study suggest that protease production by D. flagrans (AC001) in liquid medium was optimized by MgSO4, CuSO4 and casein, showing that the optimized enzymatic extract exerted larvicidal activity on cyathostomins and therefore may contribute to large-scale industrial production.

Monogenean parasites of introduced pumpkinseed Lepomis gibbosus (Centrarchidae) in the Danube River Basin.

Abstract: The pumpkinseed, Lepomis gibbosus, a centrarchid fish native to eastern North America, was introduced into Europe at the end of the 19th century. Lepomis gibbosus now represents one of the most successful of introduced fish species, having spread widely throughout many European countries. In this study, we collected monogenean parasites of L. gibbosus from four sites in the Danube River Basin. We recorded four monogenean species: Gyrodactylus sp., probably acquired in the area of introduction, and Onchocleidus similis, O. dispar and Actinocleidus recurvatus, species introduced together with their host. Onchocleidus similis dominated the parasite community at all sampling sites. Actinocleidus recurvatus has only been reported from southern Europe to date and, therefore, this is the first report of A. recurvatus from Central Europe and the Danube River Basin. We observed high morphological variability in both anchor pairs of A. recurvatus. Only in O. similis was there a positive correlation observed between haptor metric traits and fish host length. Differences in metric traits between native and introduced O. similis populations may reflect a difference in fish host size, the introduced fish host achieving a smaller size than fish from native populations. A detailed analysis of microhabitat distribution indicated a preference for the second gill arch for both dominant species O. similis and A. recurvatus, with dissimilar site segregation.

Current status of soil-transmitted helminthiases among pre-school and school-aged children from Ile-Ife, Osun State, Nigeria.

Abstract: (Accepted 1 August 2010; First Published Online 2 September 2010)AbstractA cross-sectional survey was conducted to determine the prevalence andintensity of soil-transmitted helminths among pre-school and school-agedchildren attending nursery and primary schools in Ile-Ife. Single stool sampleswere collected between January and March, 2009 from 352 children randomlyselected from a total of 456 children attending both private and governmentschools. The stool samples were processed using the modified Kato–Katztechnique, and then examined for the eggs of soil-transmitted helminths (STHs).One hundred and twenty-one (34.4%) samples were positive for STH eggs. Theoverall prevalences of Ascaris lumbricoides, Trichuris trichiura and hookwormwere 33.2%, 3.7% and 0.9%, respectively. The prevalence of STH infection ingovernment schools (47.8%) was significantly higher than in private schools(16.1%) (P , 0.001). The most common type of mixed infection was thecombination of A. lumbricoides and T. trichiura (6.8%). The prevalence andintensity of A. lumbricoides rose with age. The lowest prevalence and intensity(7.7%; 0.240 ^ 0.136 eggs per gram (epg)) were recorded in the 2- to 3-year-oldage group, while the highest prevalence and intensity (58.7%; 1.820 ^ 0.237epg)were recorded in children aged 10 years and above. A questionnaire surveyindicated that 73% of the children attending private school had been treated withanthelminthics less than 2 months prior to the collection of stool specimens,while 43% of the children attending government school received anthelminthictreatment during the same period. The findings indicate that STH infections areendemic among schoolchildren in Ile-Ife and that the burden of parasiticinfections is greater in government schools than in private schools.Introduction

Evaluation of a double centrifugation technique for the detection of Anoplocephala eggs in horse faeces.

Abstract: Faecal samples of 250 horses from farms with a known history of tapeworm infection were examined comparatively for cestode eggs using a double centrifugation/combined sedimentation-floatation technique. From each faecal sample, three 5 g and three 15 g subsamples were processed, each using either saturated NaCl solution, specific gravity (sp. g.) 1.2 [NaCl]; concentrated sugar solution, sp. g. 1.26 [sugar]; or concentrated ZnSO4 solution, sp. g. 1.3 [ZnSO4] for floatation. In total, faeces from 187 horses ( = 74.8%) tested 'positive' for Anoplocephala eggs. Percentages of samples testing 'positive' for Anoplocephala ova were: 57.2% for 5 g faeces/NaCl, 66% for 15 g faeces/NaCl, 66% for 5 g faeces/sugar, 72.8% for 15 g faeces/sugar, 55.6% for 5 g faeces/ZnSO4, and 61.2% for 15 g faeces/ZnSO4, respectively. Processing of 15 g faecal samples resulted in a significant (P < 0.05; McNemar's χ2-test) increase in the percentage of Anoplocephala egg detection compared to processing of 5 g samples for all floatation solutions. By processing 15 g faecal samples using sugar solution for floatation, 97.3% of all samples that tested 'positive' for Anoplocephala eggs were identified; there was no significant difference between the rate of samples that tested 'positive' using 15 g faeces/sugar (72.8%) and the total rate of samples that tested 'positive' (74.8%). Conversely, percentages of 'positive' samples from other test combinations were significantly (P < 0.0001, McNemar's χ2-test) lower than the total rate of samples testing 'positive'. Processing faecal samples using sugar solution for floatation gave significantly (P < 0.05, Wilcoxon test) higher Anoplocephala egg counts than using NaCl and ZnSO4 solutions, for both 5 g and 15 g faecal samples. The double centrifugation technique using 15 g faecal samples and concentrated sugar solution for floatation appeared to offer an advantage for the detection of Anoplocephala eggs in horse faeces compared to the other test combinations.

An evolutionary perspective on gastrointestinal nematodes of sheep.

Abstract: The purpose of this paper was to discuss from an evolutionary perspective the interaction between domestic sheep (Ovis aries) and their gastrointestinal nematodes. Although evolution is the central theme of biology, there has been little attempt to consider how evolutionary forces have shaped and continue to shape the relationships between domestic animals and their parasite community. Mathematical modelling of the host-parasite relationship indicated that the system is remarkably robust to perturbations in its parameters. This robustness may be a consequence of the long coevolution of host and parasites. Although nematodes can potentially evolve faster than the host, coevolution is not dominated by the parasite and there are several examples where breeds of cattle or sheep have evolved high levels of resistance to disease. Coevolution is a more equal partnership between host and nematode than is commonly assumed. Coevolution between parasites and the host immune system is often described as an arms race where both host immune response genes and parasite proteins evolve rapidly in response to each other. However, initial results indicate that nematode antigens are not evolving rapidly; the arms race between the immune system and nematodes, if it exists, is happening very slowly. Fisher's fundamental theorem of natural selection states that genes with positive effects on fitness will be fixed by natural selection. Consequently, heritable variation in fitness traits is expected to be low. Contrary to this argument, there is considerable genetic variation in resistance to nematode infection. In particular, the heritabilities of nematode-specific IgA and IgE activity are moderate to high. The reasons for this apparent violation of the fundamental theorem of natural selection are not clear but several possible explanations are explored. Faecal nematode egg counts increase at the beginning of the grazing season - a phenomenon known as the periparturient rise. This increase benefits host and parasite and appears to be a consequence of coevolution. In conclusion, an evolutionary perspective can shed light on many aspects of the host-parasite relationship in domestic animals.

Intestinal helminths induce haematological changes in dogs from Jabalpur, India

Abstract: The effect of canine intestinal helminths on the haematological profile of 200 dogs, of both sexes and variable age, visiting university veterinary clinics for routine examination was investigated. The dogs were assigned to parasitized (n = 39) and non-parasitized (n = 161) groups of animals. Coprological examination revealed a 19.5% prevalence of different species of the helminths. Of these animals, 10.25% had mixed infections with Ancylostoma caninum, Toxascaris spp. and Dipylidium caninum. The intensity of A. caninum infection was the highest, with mean egg counts of 951.43 (standard error 88.66), followed by Toxascaris 283.33 (standard error 116.81) and D. caninum. The parasitized animals had significantly lower levels of haemoglobin, packed cell volume and total erythrocyte counts than non-parasitized animals (P < 0.01). Values of other parameters, except for lymphocytes and eosinophils, were not different between the two groups. Analyses of the haematological profile revealed normocytic hypochromic anaemia in the parasitized group of animals.

Heterorhabditis atacamensis n. sp. (Nematoda: Heterorhabditidae), a new entomopathogenic nematode from the Atacama Desert, Chile.

Abstract: A new Heterorhabditis species of entomopathogenic nematode was isolated from soil of the Atacama Desert in Chile The new species is characterized by morphometrics of the infective juvenile (IJ) with length (L) = 611 (578–666) μm, head to excretory pore length (EP) = 115 (101–126) μm, tail = 69 (62–79) μm long, (EP/tail) × 100 (E%) = 165 (149–182) and L/maximum body diameter (ratio a) = 28 (25–31) The male has spicules 45 (40–49) μm long, gubernaculum 20 (17–22) μm long and (spicule length/anal body diameter) × 100 (SW%) = 205 (179–249) The hermaphroditic adult has shallow cuticular folds immediately anterior and posterior to the vulva, a slight post-anal swelling and a finely rounded tail terminus Morphologically, H atacamensis n sp resembles H safricana, H marelatus, H downesi and H amazonensis, but can be distinguished by characters of adult and IJ stages In particular, for adult males, H atacamensis n sp differs from H amazonensis by the number and orientation of the genital papillae and from H downesi by the position of the excretory pore; by the shape of the female tail terminus from H downesi and by the position of the IJ hemizonid from H marelatus Heterorhabditis atacamensis n sp is further characterized by internal transcribed spacer (ITS) and D2D3 rDNA sequences, the closest species, H safricana, being separated by 13 bp across 730 bp of the ITS (incorporating ITS1 (partial sequence), 58S (complete sequence), ITS2 (complete sequence)) and 5 bp across 592 bp of the partial 28S (incorporating D2D3) sequence The morphological and molecular data confirm that H atacamensis n sp is a valid species

Point prevalence of bovine fascioliasis and the influence of chemotherapy on the milk yield in a lactating bovine population from the district of Toba Tek Singh, Pakistan.

Abstract: This paper provides an estimation of the point prevalence of fascioliasis and its economic impact in terms of increased milk yield after chemotherapy of a bovine population from the district of Toba Tek Singh, Punjab, Pakistan. A total of 2400 cattle and buffaloes were examined quantitatively using the McMaster egg-counting technique. Infected cattle and buffaloes (50 of each) were randomly selected and each divided into two groups of 25 animals. Groups A (buffaloes) and C (cattle) were treated with oxyclozanide (orally, 16.6 mg kg− 1 body weight). Groups B and D served as negative controls for buffaloes and cattle, respectively. Pre- and post-treatment milk yield was recorded to determine if there were any changes in milk yield after treatment. Of 2400 faecal samples analysed, 654 (27.25%) were positive for Fasciola spp. with a mean number of eggs per gram (EPG) of 503.2. The point prevalence and worm burden of fascioliasis was significantly higher (OR = 2.13; P < 0.05) in buffaloes (34.58%; 415/1200; mean EPG maximum likelihood = 521.4) as compared to that of cattle (19.92%; 239/1200; mean EPG maximum likelihood = 415.8). Among the parasite species, F. gigantica (19.88%; 477/2400) was predominant (OR = 3.12; P < 0.05) as compared to F. hepatica (7.38%; 177/2400). An average daily increase of 0.67 and 0.87 litres of milk, with 0.41% and 0.37% more fat per animal, was observed in oxyclozanide-treated buffaloes and cattle, respectively. The economic value of reduced production of infected animals was estimated as US$0.33 and 0.32 per animal per day for cattle and buffaloes, respectively.

Resistance and resilience of traditionally managed West African Dwarf goats from the savanna zone of northern Nigeria to naturally acquired trypanosome and gastrointestinal nematode infections.

Abstract: A survey was conducted of gastrointestinal nematode infections and trypanosomosis in Nigerian West African Dwarf (WAD) goats from the savanna region of the country. Animals were screened at two markets, Gboko and Akpagher, from the beginning of April until the end of September, coinciding with the end of the dry season and the first 5 months of the wet season. Of 1054 goats that were examined, 80.5% carried gastrointestinal (GI) nematodes belonging to the genera Haemonchus (61.0%), Oesophagostomum (21.0%) and Trichostrongylus (17.9%). Faecal egg counts (FEC) increased very slowly but significantly from April to maximum levels in September, and varied marginally between the two market sources. The majority of goats (68.8 and 70.1% at the two markets) had low FEC not exceeding 50 eggs/g (epg). FEC did not differ significantly between the sexes or between age classes. Packed cell volume (PCV) also declined significantly with month of the study, but was affected by host sex (a significant month x sex interaction) being generally higher in male animals throughout the period. There was a highly significant negative correlation between log₁₀(FEC+1) and PCV, when all other factors had been taken into account. Body condition scores (BCS) also declined with month of the study, but there was a marked difference between the two sexes, with male animals generally showing a greater stability of BCS across the months compared with females. Trypanosome infections were found in only 4% of the goats and only during the rainy season. Most infections (92.86%) were caused by Trypanosoma brucei alone although T. vivax and T. congolense were occasionally detected. Overall, the majority of goats sampled each month maintained generally good body condition (BCS 3.0-5.0), normal or slightly reduced PCV, even when concurrently infected with trypanosomes and GI nematodes. However, four concurrently infected goats showed signs of overt anaemia during periods of peak infection, during the late rainy season, with marked reductions in PCV (< 15%). Two of the infected goats were also in poor body condition with BCS of < 2.0. There was no evidence of additive or synergistic pathogenic effects of the two parasites. These results are discussed in the context of the unexpectedly strong resistance and resilience of the savanna WAD ecotype to its native strains of GI nematode and trypanosome parasites.

The occurrence of the larval cestode Cysticercus fasciolaris in rodent populations from the Cuxtal ecological reserve, Yucatan, Mexico

Abstract: Cysticercus fasciolaris is the larval stage of the cestode Taenia taeniaeformis, whose definitive hosts are mainly cats. This larval stage uses a wide variety of small rodents, and occasionally birds and humans, as intermediate hosts. In the Yucatan, there are no reports of the presence of this cestode in animal populations. The aim of this study was to evaluate the occurrence of C. fasciolaris in rodent populations from the Cuxtal ecological reserve, Yucatan, Mexico. Trapping of rodents was conducted from October 2009 to April 2010 in 40 households in Molas, in which Sherman traps were placed both inside and outside backyards. Rodents were dissected to inspect the liver for the presence of the worm. To determine risk factors associated with infection, univariate analysis was performed using sex, age, species, trapping site, and season as independent variables. Variables with a P value < 0.2 were analysed using a logistic regression model. In this study, 411 individuals of six rodent species were trapped; Mus musculus was the most abundant (78%), followed by Rattus rattus (13%) and the wild species Peromyscus yucatanicus, Ototylomys phyllotis, Heteromys gaumeri and Reithrodontomys gracilis (9%). Only 7.5% (n = 31) of M. musculus and R. rattus were infected with C. fasciolaris (demonstrated by the presence of liver cysts) with a prevalence of 9.0% and 3.5%, respectively. Both adults and male mice were 4.33 and 3.46 (OR values) times more likely to have C. fasciolaris than juveniles and females respectively. We can conclude that in the Cuxtal Reserve, Yucatan, Mexico, the prevalence of C. fasciolaris is higher in M. musculus, and that adult males had a higher probability of infection. Wild species, mainly P. yucatanicus, were not found to be infected with the cestode, but its presence in the backyards of households could result in a potential risk of acquiring this infection.

Development and characterization of monoclonal antibodies against WbSXP-1 for the detection of circulating filarial antigens.

Abstract: The importance of developing effective assays to diagnose, monitor and evaluate human lymphatic filariasis has been emphasized by the World Health Organization. Presently, few immunodiagnostics are available for filarial monitoring programmes. The Wuchereria bancrofti (Wb) SXP-1 parasite protein, with 84% homology to Brugia malayi (Bm) SXP-1, was found to be highly immunogenic. WbSXP-1 is one among the diagnostic candidate molecules that were used for developing a rapid-antibody-flow-through diagnostic kit for filariasis. Studies were initiated with the aim of developing monoclonal antibodies against recombinant WbSXP-1 and prospective applications for the detection of both circulating Wb and Bm antigens in serum samples from infected individuals. The monoclones 1A6C2 of subclass IgG1k, and 2A12F8 of class IgM, specifically detected Wb and Bm microfilaria isolated from patients and did not show cross-reactivity with other filarial recombinant antigens. We anticipate that this work will address the problems faced in the rapid diagnosis of human lymphatic filariasis in endemic areas in developing countries.

Latitudinal gradient in the taxonomic composition of parasite communities.

Abstract: Although latitudinal gradients in diversity have been well studied, latitudinal variation in the taxonomic composition of communities has received less attention. Here, we use a large dataset including 950 surveys of helminth endoparasite communities in 650 species of vertebrate hosts to test for latitudinal changes in the relative contributions of trematodes, cestodes, nematodes and acanthocephalans to parasite assemblages. Although the species richness of helminth communities showed no consistent latitudinal variation, their taxonomic composition varied as a function of both host type and latitude. First, trematodes and acanthocephalans accounted for a higher proportion of species in helminth communities of fish, whereas nematodes achieved a higher proportion of the species in communities of bird and especially mammal hosts. Second, the proportion of trematodes in helminth communities of birds and mammals increased toward higher latitudes. Finally, the proportion of nematodes per community increased toward lower latitudes regardless of the type of host. We present tentative explanations for these patterns, and argue that new insights in parasite community ecology can be gained by searching for latitudinal gradients not only in parasite species richness, but also in the taxonomic composition of parasite assemblages.

The occurrence of Austrodiplostomum compactum (Lutz, 1928) (Digenea: Diplostomidae) metacercariae in the eyes of loricariid fish (Siluriformes: Osteichthyes: Loricariidae) from Brazil.

Abstract: The aim of this study was to report the occurrence of Austrodiplostomum compactum metacercariae in the eyes of 98 specimens of loricariid fish (Hypostomus ancistroides, H. hermanni, H. iheringii, H. margaritifer, H. regani, H. strigaticeps, Hypostomus sp. and Megalancistrus parananus) from the Chavantes reservoir (23°07′36″S and 49°37′35″W) located in the rio Paranapanema, upper Parana river basin, municipality of Ipaussu, Sao Paulo State, Brazil. Fish were collected from October 2007 to February 2009 using nylon monofilament gill nets and transported to the field laboratory where they were euthanized and the eyes were taken and examined under a stereomicroscope. Hypostomus ancistroides and M. parananus were not infected by this diplostomid. Hypostomus hermanni and H. margaritifer were represented by only one specimen but both had a high intensity of A. compactum metacercarie (27 and 35, respectively). Hypostomus strigaticeps (n = 45) and H. iheringii (n = 28) were the most representative specimens and the prevalence, mean intensity of infection and mean abundance were 24.4%, 10.3 and 2.7, and 64.2%, 13.1 and 8.4, respectively. No correlation was observed between the intensity of infection and the standard length (r = − 0.223; P = 0.827) and weight (r = 0.03; P = 0.779) of studied fish. Similarly, linear regression among these variables showed a poor correlation and indicated that the infection by A. compactum metacercariae occurs similarly in small and large fish specimens. A seasonal pattern of infection was not observed. Hypostomus hermanni, H. iheringii, H. margaritifer and H. strigaticeps were new hosts recorded for A. compactum metacercariae. A review of morphometric data of A. compactum metacercariae is presented.

Geographical distribution of cercarial dermatitis in Norway.

Abstract: Bird schistosomes can cause a disease called cercarial dermatitis, or swimmer's itch, in humans. The disease occurs when people have direct contact with fresh water or sea water containing the free-swimming cercariae of the flukes. The symptoms are well known, and include intense itching, maculae, papulae, urticariae and, in some cases, local oedema with enlarged lymph nodes and fever. In this study, we present the geographical distribution of freshwater cercarial dermatitis in Norway. The study is based on random reports obtained from both individuals and physicians treating patients with itching skin rash after freshwater bathing. The first case of cercarial dermatitis in Norway was reported in 1980 and was traced to a lake near Trondheim in the central part of Norway. In the following years, an increasing number of cases were reported, especially in southern Norway. However, case reports are distributed almost all over the country, even from lakes in northern Norway. As far as we know, these are the northernmost case reports in Europe. So far, only one fluke species (Trichobilharzia franki) from a single infected snail (Radix auricularia) has been identified in Norway. However, unidentified schistosomatid ocellate cercariae have been found on several occasions in snails collected from six lakes where swimmer's itch is frequently reported. Future studies should be performed to identify the fluke species, as well as the most important snail and bird hosts, in Norwegian lakes.

Phylogeny and taxonomy of Potamotrygonocotyle Mayes, Brooks & Thorson, 1981 (Monogenoidea: Monocotylidae) with a description of four new species

Abstract: The marine-derived stingrays of Potamotrygonidae, endemic to South American river systems, host an interesting parasite fauna equally related to marine lineages. Among those lineages, the diversity and phylogenetic relationships within Potamotrygonocotyle - a monocotylid monogenoidean specific to potamotrygonids - are poorly known, since 9 of 10 species attributed to this genus have been described in the past 3 years. Here, we readdress the diversity of Potamotrygonocotyle after examining the gills of 436 potamotrygonid individuals representing 12 described and 14 potentially undescribed species of freshwater stingrays from 19 major river systems of South America (i.e. sub-basins). We recognized 12 valid species within the parasite genus, of which four are described in this study. Our taxonomic decisions were based on the phylogenetic analysis of 14 ingroup terminal taxa and 12 morphological characters, which resulted in the following hypothesis of sister-group relationships: ((P. dromedarius, P. tatianae sp. nov.), (P. rionegrense, P. auriculocotyle sp. nov., ((P. quadracotyle, P. umbella), (P. septemcotyle sp. nov., (P. chisholmae, P. uruguayense)), (P. tsalickisi, P. eurypotamoxenus, P. rarum, (P. tocantinsense sp. nov., P. aramasae))))). According to our hypothesis, the absence of autapomorphic features for some nominal species, and the re-evaluation of morphological variation among populations, led us to consider P. eurypotamoxenus and P. uruguayense as junior synonymys of P. tsalicksi and P. chisholmae, respectively. Finally, we address the importance of biogeographic and host representation, in order to fully understand the patterns of morphological variation and host specificity within this group. We found that hypotheses of species delimitation depend greatly on efforts to sample specimens throughout its distributional range and that host specificity within this genus varies dramatically among lineages.

Elaphostrongylus cervi in a population of red deer (Cervus elaphus) and evidence of cerebrospinal nematodiasis in small ruminants in the province of Varese, Italy

Abstract: Thirty-one faecal samples were collected from red deer in the northern area of Varese, in the Italian region of Lombardy, between August and October 2008. The animals had either been hunted or accidently killed. Examination for internal parasites showed a prevalence of 45.2% for Elaphostrongylus cervi larvae and species identification was confirmed by polymerase chain reaction (PCR). Ninety-seven faecal samples were also collected from two goat flocks grazing in the same area between December 2007 and May 2008. These showed a prevalence of 74.7% for lungworms. Furthermore, the central nervous systems from five goats and one sheep from this area with a history of neurologically related lameness were examined. Histopathology confirmed E. cervi cerebro-spinal nematodiasis in five cases out of six. This study demonstrates E. cervi transmission from wild to domestic ruminants when the animals graze in the same area, and the possible occurrence of clinical disease in infected goats and sheep associated with high prevalence in deer.

Efficacy of combined treatment with albendazole and baicalein against eosinophilic meningitis induced by Angiostrongylus cantonensis in mice.

Abstract: Angiostrongylus cantonensis infection causes eosinophilic meningitis in humans. Baicalein is a flavonoid originally isolated from the roots of Scutellaria baicalensis Georgi. In this study we evaluated the efficacy of the combination of albendazole and baicalein for treating eosinophilic meningitis in BALB/c mice. Therapeutic efficacy included the survival time, body weight, neurological function, leucocyte and eosinophil counts, eotaxin concentration, matrix metalloproteinase-9 (MMP-9) activity, larval recovery and histopathological examination. The results showed that the combination of albendazole and baicalein was more effective than either drug administered singly. Combination therapy increased the survival time, decreased body weight loss, neurological dysfunction, leucocyte response, eotaxin concentration and MMP-9 activity. Our results suggest that the combination of albendazole and baicalein may exhibit synergistic beneficial effects in the treatment of eosinophilic meningitis induced by A. cantonensis.