Showing papers in "Parasitology Research in 2004"
TL;DR: A reverse line blotting (RLB) assay was developed enabling direct, concurrent, highly specific and sensitive identification of virtually all presently known ovine/caprine piroplasm species and could be considerably enhanced to detect a parasitemia level of at least 10-12% by reamplification of PCR products (nested PCR) thereby substantially increasing the possibility of identifying carrier animals.
Abstract: Characteristic sequence signatures were identified within the hypervariable region 4 (V4 region) of the small ribosomal RNA gene of ovine/caprine piroplasm species including Theileria lestoquardi, T. ovis , T. separata , Babesia ovis , B. motasi , B. crassa [comprising strains B. crassa (Iran) and B. crassa (Turkey)] and several novel species: Theileria sp. 1 (China), Theileria sp. 2 (China) and Babesia sp. (China), [comprising strain Babesia sp. (Lintan), and Babesia sp. (Ningxian)] as defined previously. Based on the ascertained gene variations a reverse line blotting (RLB) assay was developed enabling direct, concurrent, highly specific and sensitive identification of virtually all presently known ovine/caprine piroplasm species. All probes bound to their respective target sequence only, therefore, no cross-reaction was observed resulting in clear recognition of either individual strains, species or groups. No signal was observed when ovine and caprine genomic DNA was used as the control, demonstrating that the signals are due to the presence of parasite DNA in investigated samples. Furthermore, the sensitivity of RLB could be considerably enhanced to detect a parasitemia level of at least 10-12% by reamplification of PCR products (nested PCR) thereby substantially increasing the possibility of identifying carrier animals.
208 citations
TL;DR: PCR-based genotype classification is a powerful tool with which to analyse genotypes of Blastocystis isolates obtained from clinical samples and it could not be shown that the specific genotype correlated with the pathogenic potential of B. hominis.
Abstract: Since the genotype of human Blastocystis hominis isolates is highly polymorphic, PCR-based genotype classification using known sequenced-tagged site (STS) primers would allow the identification or classification of different genotypes. Five populations of human B. hominis isolates obtained from Japan, Pakistan, Bangladesh, Germany, and Thailand were subjected to genotype analysis by using seven kinds of STS primers. Ninety-nine out of 102 isolates were identified as one of the known genotypes, while one isolate from Thailand showed two distinct genotypes and two isolates from Japan were negative with all the STS primers. The most dominant genotype among four populations, except for all four isolates from Thailand, was subtype 3 and it varied from 41.7% to 92.3%. The second most common genotype among four populations was either subtype 1 (7.7–25.0%) or subtype 4 (10.0–22.9%). Subtype 2, subtype 5, and/or subtype 7 were only rarely detected among the isolates from Japan and Germany, while subtype 6 was not detected. The phylogenetic position of the two isolates which were negative with all STS primers, was inferred from the small subunit rRNA (SSU rRNA) genes with the known sequence data of 20 Blastocystis isolates. Since the two isolates were positioned in an additional clade in the phylogenetic tree, this suggested they were a new genotype. These results demonstrated that PCR-based genotype classification is a powerful tool with which to analyse genotypes of Blastocystis isolates obtained from clinical samples. In addition, two groups of the isolates from 15 symptomatic and 11 asymptomatic patients in Bangladesh were compared with the PCR-based subtype classification. Since both groups were only classified into two distinct genotypes of subtype 1 or subtype 3 and no statistically significant difference was observed between the two groups, in this study it could not be shown that the specific genotype correlated with the pathogenic potential of B. hominis.
200 citations
TL;DR: The combination of egg isolation and PCR will be of value in epidemiological studies when investigating environmental samples and the combination of DNA of other strains of E. granulosus and of 14 helminth species which inhabit the intestines of dogs was investigated.
Abstract: Polymerase chain reaction (PCR) for the identification of eggs of the tapeworm Echinococcus granulosus (“sheep strain”) was evaluated with primers derived from mitochondrial sequences. Specificity of these primers was confirmed by investigating DNA of other strains of E. granulosus and of 14 helminth species which inhabit the intestines of dogs. This PCR assay was used to investigate 131 purged dogs from Kazakhstan. Eighteen dogs harboured Echinococcus worms, ten of them in mixed infections with Taenia spp. Coproantigen detection was positive in 15 and taeniid eggs could be recovered from 13 of these specimens. Eight of the egg-containing samples were positive in the PCR for E. granulosus and four in a Echinococcus multilocularis -specific PCR revealing one mixed infection. Egg-containing faeces from two dogs harbouring both Taenia spp. and Echinococcus spp. were negative in both PCRs. The combination of egg isolation and PCR will also be of value in epidemiological studies when investigating environmental samples.
157 citations
TL;DR: A survey was carried out in Bulgaria to determine the presence of free-living amoebae (FLA) from environmental sources and identified four isolates belonging to the genus Acanthamoeba, which exhibited morphological characteristics matching those of Hartmannella spp.
Abstract: A survey was carried out in Bulgaria to determine the presence of free-living amoebae (FLA) from environmental sources. In 171 (61.1%) of 280 samples, isolates of Acanthamoeba with group II or III morphology, as well as Hartmannella spp. were recovered. Five isolates named “6” (artificial lake), Ep (lake), G2 (soil), R4* (river) and PK (spring water)—all exhibiting a highly efficient proliferation in axenic cultures—were subsequently cloned and subjected to molecular analyses for identification and genotyping In accordance with morphological findings, PCR-based analyses identified four isolates (6, Ep, G2, R4*) belonging to the genus Acanthamoeba. Confirmation of these findings was obtained by phylogenetic analysis using partial sequencing of the 18S rDNA (ASA.S1) Acanthamoeba-gene. Comparison of these sequences with corresponding regions from other Acanthamoeba strains available from GenBank sorted all four isolates into the sequence type group T4 that contains most of the pathogenic Acanthamoeba strains already identified. The fifth isolate (PK) exhibited morphological characteristics matching those of Hartmannella, and scored negative in the Naegleria fowleri and Acanthamoeba PCRs.
155 citations
TL;DR: This review examines food-borne intestinal trematodiases associated with species in families of the Digenea related to Echinostomatidae and Heterophyidae, and emphasis in the review is placed on species in these families.
Abstract: Food-borne trematodiases still remain a public health problem world-wide, despite changes in eating habits, alterations in social and agricultural practices, health education, industrialization, environmental alteration, and broad-spectrum anthelmintics. Food-borne trematodiases usually occur focally, are still persistently endemic in some parts of the world, and are most prevalent in remote rural places among school-age children, low-wage earners, and women of child-bearing age. Intestinal fluke diseases are aggravated by socio-economic factors such as poverty, malnutrition, an explosively growing free-food market, a lack of sufficient food inspection and sanitation, other helminthiases, and declining economic conditions. Control programs implemented for food-borne zoonoses and sustained in endemic areas are not fully successful for intestinal food-borne trematodiases because of centuries-old traditions of eating raw or insufficiently cooked food, widespread zoonotic reservoirs, promiscuous defecation, and the use of “night soil” (human excrement collected from latrines) as fertilizer. This review examines food-borne intestinal trematodiases associated with species in families of the Digenea: Brachylaimidae, Diplostomidae, Echinostomatidae, Fasciolidae, Gastrodiscidae, Gymnophallidae, Heterophyidae, Lecithodendriidae, Microphallidae, Nanophyetidae, Paramphistomatidae, Plagiorchiidae, and Strigeidae. Because most of the implicated species are in the Echinostomatidae and Heterophyidae, emphasis in the review is placed on species in these families.
143 citations
TL;DR: Euphausiids have no importance at all for the successful transmission of A. simplex in the Norwegian Deep, demonstrating that this nematode is able to select definite host species depending on the locality, apparently having a very low level of host specificity.
Abstract: Copepoda (Calanus finmarchicus n=1,722, Paraeuchaeta norvegica n=1,955), Hyperiidae (n=3,019), Euphausiacea (Meganyctiphanes norvegica n=4,780), and the fishes Maurolicus muelleri (n=500) and Pollachius virens (n=33) were collected in the Norwegian Deep (northern North Sea) during summer 2001 to examine the importance of pelagic invertebrates and vertebrates as hosts of Anisakis simplex and their roles in the transfer of this nematode to its final hosts (Cetaceans). Third stage larvae (L3) of A. simplex were found in P. norvegica, M. muelleri and P. virens. The prevalence of A. simplex in dissected P. norvegica was 0.26%, with an intensity of 1. Prevalences in M. muelleri and P. virens were 49.6% and 100.0%, with mean intensities of 1.1–2.6 (total fish length ≥6.0–7.2) and 193.6, respectively. All specimens of C. finmarchicus and M. norvegica examined were free of anisakid nematode species and no other parasites were detected. P. norvegica, which harboured the third stage larvae, is the obligatory first intermediate host of A. simplex in the investigated area. Though there was no apparent development of larvae in M. muelleri, this fish can be considered as the obligatory second intermediate host of A. simplex in the Norwegian Deep. However, it is unlikely that the larva from P. norvegica can be successfully transmitted into the cetacean or pinniped final hosts, where they reach the adult stage. An additional growth phase and a second intermediate host is the next phase in the life cycle. Larger predators such as P. virens serve as paratenic hosts, accumulating the already infective stage from M. muelleri. The oceanic life cycle of A. simplex in the Norwegian Deep is very different in terms of hosts and proposed life cycle patterns of A. simplex from other regions, involving only a few intermediate hosts. In contrast to earlier suggestions, euphausiids have no importance at all for the successful transmission of A. simplex in the Norwegian Deep. This demonstrates that this nematode is able to select definite host species depending on the locality, apparently having a very low level of host specificity. This could explain the wide range of different hosts that have been recorded for this species, and can be seen as the reason for the success of this parasite in reaching its marine mammal final hosts in an oceanic environment.
132 citations
TL;DR: The fascioliasis situation in humans and livestock of Iranian Mazandaran is analysed for the first time and forms intermediate between Fasciola hepatica and F. gigantica appear in addition to both species.
Abstract: The fascioliasis situation in humans and livestock of Iranian Mazandaran is analysed for the first time. Coprological studies showed 7.3% and 25.4% global prevalences in sheep and cattle, respectively. Studies in slaughterhouses indicate that sheep and cattle may be the main reservoir species, buffaloes may play local roles in the transmission, and goats and horses probably only participate sporadically. Morphometric studies by computer image analysis showed that forms intermediate between Fasciola hepatica and F. gigantica appear in addition to both species. A total of 107 infected humans were diagnosed during the 1999-2002 period, which suggests that fascioliasis may be widespread. The absence of differences in human fascioliasis among gender and age groups differs from other human endemic areas. Both human and animal infections show marked differences between western and eastern Mazandaran. Traditions in herbal condiments for human consumption, methods of animal husbandry and annual rainfall may explain the higher prevalences in western Mazandaran.
125 citations
TL;DR: It is demonstrated that the crude methanolic extract of leaves of Mucuna pruriens and the petroleum-ether extract of seeds of Carica papaya have potential for effective control of I. multifiliis.
Abstract: The ciliate Ichthyophthirius multifiliis is among the most pathogenic parasites of fish maintained in captivity. In the present study, the effects of the crude methanolic extract of leaves of Mucuna pruriens and the petroleum-ether extract of seeds of Carica papaya against I. multifiliis were investigated under in vivo and in vitro conditions. Goldfish (Carassius auratus auratus) infected with the parasites were immersed for 72 h in baths with M. pruriens extract, and for 96 h in baths with C. papaya extract. There was a 90% reduction in numbers of I. multifiliis on fish after treatment in baths of each plant extract at 200 mg l−1 compared to untreated controls. Consequently, parasite-induced fish mortality was reduced significantly. A complete interruption of trophont recruitment was achieved by immersion in the M. pruriens extract. In vitro tests led to a 100% mortality of I. multifiliis in 150 mg/l M. pruriens extract, and in 200 mg/l of C. papaya extract after 6 h. Although the active constituents of the medicinal plant extracts are still unknown, we have demonstrated that they have potential for effective control of I. multifiliis.
105 citations
TL;DR: The data show that F. hepatica can metabolise triclabendazole sulphoxide into its relatively inert sulphone metabolite, and the mechanism of tricLabendazoles resistance in F. hepatatica is discussed.
Abstract: Benzimidazole anthelmintics are widely used against nematode, cestode and trematode parasites. The drugs undergo several enzyme-mediated reactions within the host animal that produce a number of metabolites. Although it has been shown that certain helminths, including Fasciola hepatica, can metabolise albendazole, nothing is known regarding the ability of the liver fluke to metabolise triclabendazole, which is the major flukicidal compound currently on the market. In the current study, adult triclabendazole-susceptible flukes were treated with triclabendazole sulphoxide in vitro, and the metabolism of the drug was monitored by high performance liquid chromatography. The data show that F. hepatica can metabolise triclabendazole sulphoxide into its relatively inert sulphone metabolite. Parallel experiments using triclabendazole-resistant flukes showed that the conversion of triclabendazole sulphoxide to triclabendazole sulphone was on average 20.29% greater in the resistant flukes compared with the susceptible flukes. The results are discussed with regard to the mechanism of triclabendazole resistance in F. hepatica.
104 citations
TL;DR: A high degree of genetic polymorphism, represented by five distinct genotypes (BEB1–BEB5), was found among the E. bieneusi isolates from cattle.
Abstract: In this study, 338 fecal samples were analyzed for Enterocytozoon bieneusi from cattle farms in Florida, Maryland, Michigan, New York, North Carolina, Pennsylvania, Virginia, and Portugal. The internal transcribed spacer region (392 bp) of the rRNA gene of E. bieneusi was amplified using a nested PCR protocol. Thirty-two E. bieneusi-PCR positive samples were sequenced. A high degree of genetic polymorphism, represented by five distinct genotypes (BEB1-BEB5), was found among the E. bieneusi isolates from cattle. Most of the isolates formed a distinct cluster consisting of only the four cattle genotypes, but six isolates of a genotype clustered together with E. bieneusi genotypes from humans and other domestic animals. Therefore, only some E. bieneusi isolates from cattle may be of public health importance.
104 citations
TL;DR: Allergic symptoms are the most frequent manifestation of A. simplex parasitism and the latency of appearance of symptoms in patients positive for Anisakis larvae, patients without larvae at gastroscopy and patients without digestive symptoms are compared.
Abstract: We analysed patients with allergic or digestive symptoms after seafood ingestion in order to assess a correct diet in Anisakis simplex sensitised individuals. A total of 120 patients who suffered allergic and/or digestive symptoms after marine food ingestion were studied. We performed skin prick tests for A. simplex and seafood, total serum and specific serum immunoglobulin E to A. simplex in the acute stage and 1 month later. A gastroscopy was carried out to find larvae in those patients with persistent abdominal pain. A challenge with non-infective larvae was performed to assess a correct diet. Some 96 patients were sensitised to A. simplex. Gastroscopy was performed in 47 and we detected larvae in 24. We compared symptoms, skin tests, total and specific IgE and the latency of appearance of symptoms in patients positive for Anisakis larvae, patients without larvae at gastroscopy and patients without digestive symptoms. There was no difference among the groups. We challenged 22 patients with frozen A. simplex larvae. After allowing deep-frozen seafood in the diet for more than 2 years, no patient suffered a reaction. At this time, we allowed all our patients well-frozen seafood without any allergic reaction occurring. Allergic symptoms are the most frequent manifestation of A. simplex parasitism. We could not find any patient allergic to the thermostable proteins of parasite.
TL;DR: Zebra mussels from throughout the Shannon River drainage area in Ireland were tested for the anthropozoonotic waterborne parasites Cryptosporidium parvum, Giardia lamblia, Encephalitozoon intestinalis, E. hellem, and Enterocytozoon bieneusi by the multiplexed combined direct immunofluorescent antibody and fluorescent in situ hybridization method and PCR.
Abstract: Zebra mussels ( Dreissena polymorpha) from throughout the Shannon River drainage area in Ireland were tested for the anthropozoonotic waterborne parasites Cryptosporidium parvum, Giardia lamblia, Encephalitozoon intestinalis, E. hellem, and Enterocytozoon bieneusi, by the multiplexed combined direct immunofluorescent antibody and fluorescent in situ hybridization method, and PCR. Parasite transmission stages were found at 75% of sites, with the highest mean concentration of 16, nine, and eight C. parvum oocysts, G. lamblia cysts, and Encephalitozoon intestinalis spores/mussel, respectively. On average eight Enterocytozoon bieneusi spores/mussel were recovered at any selected site. Approximately 80% of all parasites were viable and thus capable of initiating human infection. The Shannon River is polluted with serious emerging human waterborne pathogens including C. parvum, against which no therapy exists. Zebra mussels can recover and concentrate environmentally derived pathogens and can be used for the sanitary assessment of water quality.
TL;DR: A new electroporation protocol and expression vectors which use luciferase and green and red fluorescent proteins as reporter genes are developed and a vector containing an expression cassette designed to be targeted to the tubulin locus of the parasite is constructed.
Abstract: To improve transfection efficiency in Trypanosoma cruzi, we developed a new electroporation protocol and expression vectors which use luciferase and green and red fluorescent proteins as reporter genes. In transient transfections, the electroporation conditions reported here resulted in luciferase expression 100 times higher than the levels obtained with previously described protocols. To verify whether sequences containing different trans-splicing signals influence reporter gene expression, we compared DNA fragments corresponding to 5′ untranslated plus intergenic (5′ UTR plus Ig) regions from GAPDH, TcP2β, α- and β-tubulin and amastin genes. Vectors containing sequences derived from the first four genes presented similar efficiencies and resulted in luciferase expression in transiently transfected epimastigotes that was up to 10 times higher than that for a control vector. In contrast, the amastin 5′ UTR plus Ig resulted in lower levels of reporter gene expression. We also constructed a vector containing an expression cassette designed to be targeted to the tubulin locus of the parasite.
TL;DR: The results show that the Wistar rat is an ideal host for the propagation of strains RN94-9 and NIH:1295:1 of B. hominis, and demonstrate that the cyst form is the only transmissible form of this parasite.
Abstract: The infectivity of two Blastocystis hominis strains, RN94-9 and NIH:1295:1, was examined in 3-week-old SPF Wistar rats. The NIH:1295:1 strain, originally isolated from a guinea pig, was only able to infect rats via intracecal inoculation of the cultured organisms, while the RN94-9 strain, originally isolated from a laboratory rat, was able to infect rats by oral inoculation of the cultures due to the presence of a cystic form in the in vitro culture. Since many cysts were discharged in the feces of the infected rats, the infectivity of the concentrated cysts was compared between the two strains. Successful oral infection was observed in rats inoculated with 1×102–1×106 cysts of the RN94-9 and NIH:1295:1 strains. The infectivity of the ten cysts varied in the three experiments of ten rats, being 20–100% and 30–100% in the RN94-9 and NIH:1295:1 strains, respectively. When an uninfected normal rat was housed with five experimentally inoculated rats, the normal rat became infected, demonstrating the fecal-oral transmission of the cyst form of this parasite. These results show that the Wistar rat is an ideal host for the propagation of strains RN94-9 and NIH:1295:1 of B. hominis, and demonstrate that the cyst form is the only transmissible form of this parasite.
TL;DR: A significant alteration in the plasma disposition of ivermectin in sheep induced by verapamil may have an important impact on efficacy against resistant- or rate-limiting-parasites and on the persistency of its antiparasitic activity.
Abstract: P-Glycoprotein (P-GP) is a transport protein that participates in the mechanism of active secretion of different molecules from the bloodstream to the gastrointestinal tract. The aim of the current work was to evaluate the effect of verapamil, a P-GP substrate, on the pharmacokinetic behaviour of the anthelmintics ivermectin and moxidectin in sheep. Thirty-two sheep were divided into four groups and treated orally with either ivermectin or moxidectin alone (200 lg/kg) or co-administered with verapamil at 3 mg/kg (three times at 12 h intervals). Blood samples were collected over 30 days post-treatment and plasma was analysed to determine ivermectin and moxidectin concentrations by HPLC. The ivermectin peak concentration was signifi- cantly higher (P=0.048) after ivermectin plus verapa- mil, compared with the ivermectin alone treatment. Ivermectin plasma availability was significantly higher following co-administration (P=0.022). Verapamil had no effect on the kinetics of moxidectin. The significant alteration in the plasma disposition of ivermectin in sheep induced by verapamil, possibly due to interfer- ence with a P-GP-mediated elimination mechanism, may have an important impact on efficacy against resistant- or rate-limiting-parasites and on the persis- tency of its antiparasitic activity.
TL;DR: Heat- and/or pepsin-resistant allergens from A. simplex could explain reactions and symptoms after the ingestion of well-cooked or canned fish and was detected by 75% of the patients of this group.
Abstract: Ingestion of raw or undercooked fish can lead to infection with Anisakis simplex. Sensitized patients show specific IgE to proteins from this parasite. The aim of this study was to assess the frequency of specific IgE recognition directed to heat and/or pepsin-resistant allergens from A. simplex among sensitized patients. Twenty-seven patients with positive specific IgE and immunoblotting with a crude parasite extract were included in the study. Specific IgE detection against allergens resistant to boiling for 30 min and/or a pepsin digestion of an A. simplex extract was performed by immunoblotting. A total of 81% of the patients showed specific IgE to pepsin-resistant allergens and 67% had specific IgE to heat-resistant allergens. Thirty percent of patients recognized allergens after both treatments, one being the allergen detected by 75% of the patients of this group. Heat- and/or pepsin-resistant allergens from A. simplex could explain reactions and symptoms after the ingestion of well-cooked or canned fish.
TL;DR: In the absence of feeder cells from the host, long-term survival of the parasite depended strictly on low oxygen conditions and the presence of reducing agents in the medium and the growth of metacestode vesicles and differentiation towards the protoscolex stage only occurred in the Presence of culture medium that was preconditioned by hepatoma cells or several other immortal cell lines.
Abstract: We report here on the development of an in vitro system for the long-term cultivation of Echinococcus multilocularis larvae under axenic conditions. In the absence of feeder cells from the host, long-term survival of the parasite depended strictly on low oxygen conditions and the presence of reducing agents in the medium. Host serum supported survival of the parasite but the growth of metacestode vesicles and differentiation towards the protoscolex stage only occurred in the presence of culture medium that was preconditioned by hepatoma cells or several other immortal cell lines. On the basis of this in vitro system, future analyses on the identification of host-derived growth factors for E. multilocularis will be greatly facilitated.
TL;DR: Tungiasis causes a broad spectrum of clinical and histopathological alterations, and is a serious health threat in a typical, impoverished community in northeast Brazil.
Abstract: Tungiasis is a parasitic skin disease caused by the sand flea Tunga penetrans. This ectoparasitosis is endemic in South America, the Caribbean and sub-Saharan Africa, where it is an important but neglected health problem in resource-poor communities. As part of a study on tungiasis-related morbidity in a typical slum in Fortaleza, Brazil, we identified 86 individuals with tungiasis. Lesions were counted, classified according to the stage of development, and clinical pathology was documented. One hundred and nine lesions were biopsied and examined by histological sectioning. The patients had between 1 and 145 lesions (median 14.5), the majority occurring in clusters. In all, 77% of patients reported severe pain at the site of the lesion, and 52% had one or more nails lost or severely deformed. Intense inflammation and/or fissures hindered 45% of the patients from walking normally. Signs of superinfection were observed in 29%, and signs of generalised inflammation in 2% of patients. Clinical pathology was significantly related to the number of lesions, and the total number of parasites present correlated with the number of fleas occurring in clusters. Clinical pathology was frequently accompanied by a pathological alteration of the epidermis (predominantly hyperplasia, parakeratosis, hyperkeratosis, and spongiosis) and the dermis. Tungiasis causes a broad spectrum of clinical and histopathological alterations, and is a serious health threat in a typical, impoverished community in northeast Brazil. The clinical pathology is closely related to the parasite burden of an individual and the clustering of embedded fleas at certain predilection sites.
TL;DR: The results indicate that Haemaphysalis qinghaiensis transmit at least three species of Theileria, two which are infective to sheep and goats, but not yak and one which isinfective to yaks and cattle,but not to Sheep and goats.
Abstract: The phylogenetic relationships between six isolates of Theileria spp. infective to small ruminants, and two isolates of Theileria spp. infective to yak, all transmitted by Haemaphysalis qinghaiensis, together with the Theileria orientalis/sergenti/buffeli group and T. sinensis, were analyzed using the 18S ssrRNA gene sequence. The target DNA segment was amplified by polymerase chain reaction (PCR). The PCR product was used either for direct sequencing or was ligated to the PCR II vector for sequencing. The length of the 18S ssrRNA gene of all Theileria spp. involved in this study was around 1,740 bp. Two phylogenetic trees were inferred based on the 18S ssrRNA gene sequence of the Chinese isolates only, and Chinese isolates and other species of Theileria available in GenBank. In the first tree, the Theileria sp. infective to yaks was found to be T. sinensis. The Theileria sp. infective to small ruminants was found to be composed of two separate species of Theileria. Theileria sp. from Qinghai, Madang, Ningxian and Lintan, which was identical to the unidentified Theileria sp. described previously, is designated Theileria sp (China 1). The Theileria sp. from Longde, Zhangjiachuan and Lintan, which has not been described previously, is designated Theileria sp. (China 2) in order to avoid confusion. In the second tree, Theileria sp. (China 1) was closely related to benign Theileria, such as T. buffeli and T. sergenti, while Theileria sp. (China 2) was separated from other Theileria spp. The results indicate that H. qinghaiensis transmit at least three species of Theileria, two which are infective to sheep and goats, but not yak and one which is infective to yaks and cattle, but not to sheep and goats.
TL;DR: Compared the ability of these parasites to hydrolyze extracellular ATP and AMP, L. amazonensis promastigotes presented higher AMP hydrolytic activity, which may lead to an increased production of adenosine, which has been shown to present anti-inflammatory activity and may be involved in the establishment of the immunosuppression observed in mice infected by L. braziliensis.
Abstract: In the present study, C57BL/6 mice were inoculated with metacyclic Leishmania amazonensis or L. braziliensis promastigotes. While these animals were capable of controlling the infection by L. braziliensis, they developed chronic lesions with elevated numbers of parasites when infected by L. amazonensis. The differences in parasite control were associated with a decreased production of IFN-γ and TNF by lymph node cells from L. amazonensis-infected mice. Furthermore, these animals presented decreased spleen cell proliferation and activation of germinal centers. In addition, we compared the ability of these parasites to hydrolyze extracellular ATP and AMP. While the ATPase activity of both parasite species was similar, L. amazonensis promastigotes presented higher AMP hydrolytic activity. This increased activity may lead to an increased production of adenosine, which has been shown to present anti-inflammatory activity and may thus be involved in the establishment of the immunosuppression observed in mice infected by L. amazonensis.
TL;DR: The results suggest that the interactions between parasites and hosts are not stable in this lizard population, and the prevalence and intensity of infection were higher in adults than in juveniles.
Abstract: The study of the effect of parasites on their host populations is essential for understanding their role in host population dynamics and ecology. We describe the general field population biology of haemogregarines in the Iberian rock lizard, Lacerta monticola, examining the factors that determine the prevalence and intensity of infection. Prevalence and infection intensity were higher in adults than in juvenile lizards. The prevalence rate was higher in larger lizards, probably because they were also older and had been more often in contact with parasites during their lifetime. During the mating season, the intensity of parasite infection was greater in males than in females, probably due to immunosuppressive effects of testosterone. The parasite load had a negative effect on the body condition during the reproductive season. The results suggest that the interactions between parasites and hosts are not stable in this lizard population.
TL;DR: The data suggest that the olfactory nerve pathway is a likely route for natural infection of the brain by B. mandrillaris amebae.
Abstract: Balamuthia mandrillaris is a free-living ameba and an opportunistic agent of lethal granulomatous amebic encephalitis (GAE) in humans and other mammals. Its supposed routes of infection have been largely assumed from what is known about Acanthamoeba spp. and Naegleria fowleri, other free-living amebae and opportunistic encephalitis agents. However, formal proof for any migratory pathway, from GAE patients or from animal models, has been lacking. Here, immunodeficient mice were infected with B. mandrillaris amebae by intranasal instillation, the most likely natural portal of entry. By means of classical and immunohistology, the amebae are shown to adhere to the nasal epithelium, progress along the olfactory nerves, traverse the cribriform plate of the ethmoid bone, and finally infect the brain. A similar invasion pathway has been described for N. fowleri. The data suggest that the olfactory nerve pathway is a likely route for natural infection of the brain by B. mandrillaris amebae.
TL;DR: The helminth communities observed were basically similar, although there were marked differences in species richness, which was higher in falconiforms (except for A. gentilis) than in strigiforms, suggesting that a different explanation is needed.
Abstract: This is a survey of the helminth fauna of 285 individuals of 14 species of birds of prey (Falconiformes and Strigiformes) from Galicia (northwest Spain), namely Buteo buteo, Accipiter nisus, A. gentilis, Milvus migrans, M. milvus, Pernis apivorus, Circus pygargus, Falco tinnunculus, F. peregrinus, F. subbuteo, Tyto alba, Strix aluco, Asio otus and Athene noctua. A total of 15 helminth species were detected, namely 8 nematodes ( Eucoleus dispar, Capillaria tenuissima, Synhimantus laticeps, Microtetrameres sp., Physaloptera alata, Procyrnea leptoptera, Hovorkonema variegatum and Porrocaecum angusticolle), 4 cestodes ( Cladotaenia globifera, Paruterina candelabraria and Mesocestoides sp.), 2 trematodes ( Neodiplostomum attenuatum and Strigea falconis), and 1 acanthocephalan ( Centrorhynchus globocaudatus). The helminth communities observed were basically similar, although there were marked differences in species richness, which was higher in falconiforms (except for A. gentilis) than in strigiforms. More specifically, species richness was highest in B. buteo (13 species), followed by A. nisus (11 species). In the falconiforms, the helminth species present generally exhibited a clear relationship with host diet. In the strigiforms, by contrast, species richness was lower than expected given the host's diet, suggesting that a different explanation is needed.
TL;DR: A recent sandfly survey in Spain is described, starting in the northern Ebro Valley and continuing southeast into the Levante region of the Mediterranean coast, finding P. ariasi predominated over P. perniciosus in cooler bioclimatic zones, and this statistically significant pattern was more marked than that with higher altitudes.
Abstract: In Spain, only two of the 12 recorded species of sandflies, Phlebotomus (Larroussius) ariasi Tonnoir and P. (L.) perniciosus Newstead, are proven vectors of Leishmania infantum Nicolle, the causative agent of endemic leishmaniasis. Studies of the distributions of phlebotomine sandflies are important for evaluating the possible effects of climate warming on any northward or altitudinal range shifts of leishmaniasis or the other diseases they transmit. We describe a recent sandfly survey in Spain, starting in the northern Ebro Valley and continuing southeast into the Levante region of the Mediterranean coast. Sandflies (P. ariasi only) were found for the first time in the northern province of Alava, in the upper Ebro Valley, where cases of canine leishmaniasis have been described during the last decade. Throughout the provinces sampled, P. ariasi predominated over P. perniciosus in cooler bioclimatic zones, and this statistically significant pattern was more marked than that with higher altitudes.
TL;DR: This spermiogenesis is characterized by a flagellar rotation of about 120° and the formation of a novel ultrastructural element: a centriolar extension, which differs distinctly from other digenetic trematodes.
Abstract: The present paper describes the characteristic ultrastructural features of spermiogenesis and the spermatozoon of Monorchis parvus (Trematoda, Digenea, Monorchiidae). This spermiogenesis is characterized by a flagellar rotation of about 120° and the formation of a novel ultrastructural element: a centriolar extension. It nevertheless follows the general pattern of digeneans. It begins with the formation of a differentiation zone, comprising striated rootlets associated with two centrioles and an intercentriolar body. The mature spermatozoon presents features allowing the distinction between M. parvus and other digenetic trematodes. It possesses an original anterior extremity. The two central elements of the axonemes appear prior to the peripheral doublets. The external ornamentations of the cell membrane are formed parallel to the central elements. Another peculiarity of the male gamete is the presence of two mitochondria. M. parvus, therefore, differs distinctly from other digenetic trematodes.
TL;DR: When in vitro cultivation was used as the ‘gold standard’ for the detection of Blastocystis hominis in stool specimens, simple smear and trichrome staining showed sensitivities of 16.7% and 40.2% and specificities of 94% and 80.4%, respectively.
Abstract: When in vitro cultivation was used as the ‘gold standard’ for the detection of Blastocystis hominis in stool specimens, simple smear and trichrome staining showed sensitivities of 16.7% and 40.2% and specificities of 94% and 80.4%, respectively. In vitro cultivation also enhanced PCR amplification for the detection of B. hominis in stool specimens. Our data show the usefulness of in vitro cultivation for the detection and molecular study of B. hominis in stool specimens.
TL;DR: Despite morphological differences, a relationship between the spores in the urine of rainbow trout and T. bryosalmonae was demonstrated by binding of monoclonal and polyclonal antibodies and DNA probes specific to the parasite.
Abstract: Tetracapsuloides bryosalmonae is the myxozoan parasite causing proliferative kidney disease (PKD) of salmonid fishes in Europe and North America. The complete life cycle of the parasite remains unknown despite recent discoveries that the stages infectious for fish develop in freshwater bryozoans. During the course of examinations of the urine of rainbow trout (Oncorhynchus mykiss) with or recovering from PKD we identified spores with features similar to those of T. bryosalmonae found in the bryozoan host. Spores found in the urine were subspherical, with a width of 16 µm and height of 14 µm, and possessed two soft valves surrounding two spherical polar capsules (2 µm in diameter) and a single sporoplasm. The absence of hardened valves is a distinguishing characteristic of the newly established class Malacosporea that includes T. bryosalmonae as found in the bryozoan host. The parasite in the urine of rainbow trout possessed only two polar capsules and two valve cells compared to the four polar capsules and four valves observed in the spherical spores of 19 µm in diameter from T. bryosalmonae from the bryozoan host. Despite morphological differences, a relationship between the spores in the urine of rainbow trout and T. bryosalmonae was demonstrated by binding of monoclonal and polyclonal antibodies and DNA probes specific to T. bryosalmonae.
TL;DR: The initial stages of Naegleria fowleri meningoencephalitis in mice were immunohistochemically characterized and it was observed that after 24 h, amebas invaded the epithelium, without evidence of the disruption of the nasal mucosa.
Abstract: The initial stages of Naegleria fowleri meningoencephalitis in mice were immunohistochemically characterized following the first 8 h post-intranasal inoculation. The events found after 8 h were: (1) amebas in contact with the mucous layer of the olfactory epithelium, (2) numerous parasites eliminated by extensive shedding of the mucous layer, and (3) many organisms reaching the nasal epithelium. In contrast to other works, we observed that after 24 h, amebas invaded the epithelium, without evidence of the disruption of the nasal mucosa. In addition some trophozoites invading through the respiratory epithelium were observed, suggesting an additional invasion route. The inflammatory response detected was scarce until 30 h post-inoculation. After 96 h, the inflammatory response was severe in the olfactory bulb and brain, and the tissue damage great. Consequently, an inflammatory reaction may enhance tissue damage but apparently does not destroy amebas which seem to proliferate in the olfactory bulb.
TL;DR: The TaSP-ELISA test has proved its suitability for the diagnosis of tropical theileriosis and could be used in serological surveys to map out the prevalence of the disease or to monitor vaccination efficiencies in disease-free populations.
Abstract: The recombinant surface protein of Theileria annulata (TaSP) was used in the standardization and validation of an enzyme linked immunosorbent assay (ELISA) for the detection of circulating antibodies against tropical theileriosis. ELISA data were expressed as the percentage positivity (PP) of the reactivity of an internal positive control. A total of 50 sera samples from a disease-free area were used for the calculation of the cut-off value which served as a threshold between the positive and the negative sera samples. This was determined as the mean PP plus two standard deviations or the twice the mean PP of the results obtained with these negative samples. The obtained thresholds were 17.8% and 18.3%, respectively. Accordingly, the reactivity of 140 field sera samples collected at random from an area known to be endemic for tropical theileriosis in Sudan was determined as PP values which were then compared to the results obtained using the indirect fluorescence antibody test (IFAT) from the same samples. Both tests showed a high degree of correlation. The TaSP-ELISA had a sensitivity of 99.1% and specificity of 90.47% when taking the IFAT as a reference test. Our test has proved its suitability for the diagnosis of tropical theileriosis and could be used in serological surveys to map out the prevalence of the disease or to monitor vaccination efficiencies in disease-free populations.
TL;DR: The differences between the caged fish and the wild fish indicate that the aggregated distribution in wild fish might be determined by variations in exposure rather than variations in susceptibility between fish.
Abstract: This paper examines the relative importance of exposure and susceptibility to the infection of rainbow trout (Oncorhynchus mykiss) with the trematode parasite Diplostomum spathaceum under natural conditions. A total of 93 individually marked, similarly aged fish were introduced into three cages at regular time intervals and the intensity of infection in individuals recorded by counting parasites in live fish using ophthalmic techniques. Fish introduced into the cages became infected faster than fish that were already in the cages, indicating that fish developed resistance to infection after repeated exposure. Fish kept in the cages experienced similar levels of exposure and the distribution of parasites between these fish was not significantly different from a random distribution. In contrast, parasites from 16 Finnish wild roach populations were highly aggregated. The differences between the caged fish and the wild fish indicate that the aggregated distribution in wild fish might be determined by variations in exposure rather than variations in susceptibility between fish. This is one of the few studies to demonstrate the development of resistance in fish against the parasite under natural conditions, and to attempt to separate exposure and susceptibility as causative agents of parasite aggregation.