Showing papers in "Annals of Tropical Medicine and Parasitology in 2010"
TL;DR: The current laboratory diagnosis, epidemiology and main clinical features of both the systemic and ocular forms of human toxocariasis are reviewed to provide an updated overview of this neglected but highly prevalent human infection.
Abstract: Although human toxocariasis ranks among the most common zoonotic infections worldwide, it remains relatively unknown to the public. The causal agents are the nematode parasites Toxocara canis and T. cati, whose definitive hosts are dogs and cats, respectively. When embryonated eggs are accidentally ingested by humans, larvae hatch in the small intestine, penetrate the intestinal wall and migrate, via the bloodstream, to the liver, lungs, muscles, eye and central nervous system. Although most human infections are asymptomatic, two well-defined clinical syndromes are classically recognised: visceral larva migrans (a systemic disease caused by larval migration through major organs) and ocular larva migrans (a disease limited to the eyes and optic nerves). Two less-severe syndromes have recently been described, one mainly in children (covert toxocariasis) and the other mainly in adults (common toxocariasis). Here, the current laboratory diagnosis, epidemiology and main clinical features of both the systemic and ocular forms of human toxocariasis are reviewed. New developments in serological diagnosis are described, the available seroprevalence data are analysed, and the results of relevant clinical studies that have been published over the last decade are explored, to provide an updated overview of this neglected but highly prevalent human infection.
335 citations
TL;DR: Various aspects of the induction of IgG4 in humans and it roles in the immunomodulation of the human responses to filarial parasites are reviewed.
Abstract: Filarial parasites are known to induce a large range of immunoregulatory mechanisms, including the induction of alternatively activated macrophages and regulatory T cells. These mechanisms are used to evade and down-modulate the host's immune system, to support parasite survival. Several reports have focused on some of these mechanisms, in humans and murine models, but the complex immunoregulatory networks associated with filarial infections remain unclear. Recent publications have conferred a role for regulatory T cells in the ability of helminth parasites to modulate human immune responses, such cells promoting the induction of the non-complement-fixing immunoglobulin G4 (IgG4). High plasma concentrations of IgG4 have been reported in hypo-responsive and asymptomatic cases of helminth infection. In both human lymphatic filariasis and onchocerciasis, the asymptomatic infections are characterised by high plasma concentrations of IgG4 (compared with those of IgE) and of the complement-fixing antibodies IgG1, IgG2 and IgG3. In asymptomatic filarial infection, elevations in IgG4 are also often associated with high worm loads and with high plasma levels of the immunomodulatory interleukin-10. Here, various aspects of the induction of IgG4 in humans and it roles in the immunomodulation of the human responses to filarial parasites are reviewed.
145 citations
TL;DR: Recent developments in the understanding of immunity to blood-stage parasites, as well as the relevant key advances made in vaccine technologies over the last decade are summarized and the future challenges that face this field of vaccine research are described.
Abstract: Plasmodium falciparum malaria is a major global health problem, responsible for up to 1 million deaths each year. Major efforts have been made to develop an effective vaccine against this disease, to reduce the associated morbidity and mortality. There has already been considerable progress, with the first vaccine against the pre-erythrocytic stages of P. falciparum now en route to licensure. There remains, however, a strong scientific rationale for the development of a highly effective additional vaccine component against the blood stages of the parasite, which could be deployed in conjunction with partially effective control measures against the pre-erythrocytic stages. Here, recent progress in the clinical development of blood-stage vaccines is reviewed, including methods of antigen selection, the limitations of in-vitro assays for selecting vaccines for clinical development, and the results of recently published clinical trials. This review seeks to summarize recent developments in our understanding of immunity to blood-stage parasites, as well as the relevant key advances made in vaccine technologies over the last decade. The future challenges that face this field of vaccine research are also described.
90 citations
TL;DR: Human urinary schistosomiasis appears to be highly endemic in peri-urban/rural Nigeria and closely associated with poverty and health education that is not only of high quality but also culturally sensitive is needed.
Abstract: In Nigeria, there is only very limited epidemiological information on which the control of human urinary schistosomiasis could be based. In a cross-sectional study, therefore, the prevalences and intensities of, and risk factors for, human infection with Schistosoma haematobium infection were explored in two endemic peri-urban villages in the south-western state of Osun. The villagers' knowledge about the infection and demographic, socio-economic and environmental variables were recorded using a structured questionnaire.
Of the 1023 individuals who were investigated, 634 (62.0%) were found infected, with a mean (S.D.) overall intensity of 114.2 (327.7) eggs/10 ml urine. The subjects aged 10-14 years had both the highest prevalence (83.6%) and the highest mean (S.D.) intensity of infection [196.67 (411.7) eggs/10 ml urine]. Most (70.0%) of the subjects appeared to have no knowledge of the transmission of S. haematobium.
The results of multivariate regression analysis indicated that infection and moderate-heavy infection (i.e. >50 eggs/10 ml urine) were both associated with: a low family income, of
90 citations
TL;DR: McMonnies' indices (MMI), OSDI and the values recorded in Schirmer's tests were all significantly and positively correlated with the probability of a clinical diagnosis of dry eye (P<0.001 for each).
Abstract: McMonnies' and Ocular Surface Disease Index (OSDI) questionnaires were used to estimate the prevalence of dry eye among 400 consecutive patients aged >40 years attending the ophthalmology outpatient department of the Lady Hardinge Medical College and associated Smt Sucheta Kriplani Hospital, in New Delhi, India. These estimates were then compared with the results of various clinical tests and examinations of the same patients, including Schirmer's tests, evaluations of tear-film breakup times and fluorescein staining of corneas. Although the overall prevalence of dry eye based on OSDI was 29.25%, there was considerable age- and gender-related variation in this parameter. Compared with the younger patients, those aged >or=80 years were more likely to have OSDI that were indicative of dry eye (41.2%), and the women investigated were more likely to have dry eye (as indicated by OSDI) than the men (27% v. 12%). Occupation, however, appeared to have no effect on the risk of dry eye (P=0.952). Grittiness was the commonest complaint reported. McMonnies' indices (MMI), OSDI and the values recorded in Schirmer's tests were all significantly and positively correlated with the probability of a clinical diagnosis of dry eye (P<0.001 for each). Only patients with a Schirmer's value of <8 mm showed fluorescein staining of the cornea (P<0.005). This appears to be the first report from India in which MMI and OSDI have been significantly correlated with the probability of a clinical diagnosis of dry eye. Although the subjects were recruited in an ophthalmology department and may not have been very representative of the general population of New Delhi, dry-eye syndrome is probably common in the study area and probably has a considerable socio-economic impact. The early detection and timely management of this syndrome is important, as they can help prevent long-term sequelae and sight-threatening complications.
77 citations
TL;DR: The cockroaches collected from four buildings in central Tehran, Iran were much more likely to be found contaminated with medically important bacteria than those from the house, and those from each hospital were also morelikely to be carrying medically importantacteria internally than externally.
Abstract: Although it has been difficult to prove the direct involvement of cockroaches (i.e. insects of the order Blattaria) in the transmission of pathogenic agents to humans, such insects often carry microorganisms that are important in nosocomial infections, and their medical importance in the spread of bacteria cannot be ruled out. In houses and institutions with poor standards of hygiene, heavy infestations with cockroaches, such as the peridomestic American cockroach (Periplaneta americana L.) and the domestic German cockroach (Blattella germanica L.), can occur. In the present study, cockroaches (126 B. germanica and 69 P. americana) were collected from four buildings (three public training hospitals and one house) in central Tehran, Iran. Each insect was processed, under sterile conditions, so that the bacteria on its external surfaces and in its alimentary tract and faecal pellets could be isolated and identified. The oldest and largest of the three hospitals sampled (a 1400-bed unit built 80 years ago) appeared to be the one most heavily infested with cockroaches, and cockroaches from this hospital accounted for most (65.4%) of the isolates of medically important bacteria made during the study. No significant difference was found between the percentages of P. americana and B. germanica carrying medically important bacteria (96.8% v. 93.6%; P>0.05). At least 25 different species of medically important bacteria were isolated and identified, and at least 22 were Gramnegative. The genus of enteric bacteria most frequently isolated from both cockroach species, at all four collection sites, was Klebsiella. The cockroaches from each hospital were much more likely to be found contaminated with medically important bacteria than those from the house. The hospital cockroaches were also more likely to be carrying medically important bacteria internally than externally (84.3% v. 64.1%; P<0.05). The implications of these and other recent results, for the control of cockroaches and nosocomial infections, are discussed.
68 citations
TL;DR: This work reports the first evidence of bla OXA-48-mediated carbapenem-resistance in Enterobacteriaceae in Morocco, recovered from the same patient, one harbouring plasmid-encoded bla- OXa-48 and the other the bla
Abstract: The frequency of carbapenem resistance due to class-D beta-lactamases (i.e. oxacillinases) among the world's Enterobacteriaceae is increasing. Recently, in Morocco, two isolates of carbapenem-resistant Klebsiella pneumoniae were recovered from the same patient, one harbouring plasmid-encoded bla-(OXA-48) and the other the bla-(OXA-1) gene. This represents the first evidence of bla(OXA-48)-mediated carbapenem-resistance in Enterobacteriaceae in Morocco.
66 citations
TL;DR: A relatively high seroprevalence of (possibly primary) acute Toxoplasma infection in the pregnant women of Saudi Arabia is revealed, with the potential for transmission of the parasite to the foetuses.
Abstract: In a cross-sectional study to determine the seroprevalence of, and possible risk factors for, Toxoplasma gondii infection in the pregnant women of Saudi Arabia, all of the pregnant Saudi women attending the Al Ahsa Maternity Hospital over a 1-year period were invited to participate. In an interview with each subject, the relevant socio-demographic data and information on housing conditions, previous obstetric history and possible risk factors for Toxoplasma infection (e.g.frequency of consumption of undercooked meat, unwashed raw vegetables and/or unwashed raw fruit, contact with soil, and main sources of drinking water) were collected. Each subject was then checked for anti-Toxoplasma gondii IgG and IgM in commercial ELISA. Of the 554 expectant women investigated, 51.4% were found seropositive for anti-Toxoplasma IgG (indicating chronic infection) and 8.8% for anti-Toxoplasma IgM (indicating acute infection), with 6.1% of the women seropositive for Toxoplasma -specific IgM but seronegative for Toxoplasma-specific IgG. Acute infection was most common among the women who were relatively young, lived in rural areas and had relatively low incomes. The results of a multivariate logistic regression indicated that the significant positive predictors for chronic Toxoplasma infection were increasing age, rural residence, low family income, frequent consumption of undercooked meat, and previous obstetric problems (and/or multiparity). Although of questionable accuracy, the results of the present study revealed a relatively high seroprevalence of (possibly primary) acute Toxoplasma infection in the pregnant women, with the potential for transmission of the parasite to the foetuses.
53 citations
TL;DR: Aktas Z, 2008, CHEMOTHERAPY, V54, P101, DOI 10.1159-000118661; BROWN DFJ, 1991, J ANTIMICROB CHEMOTH, V27, P185,doi 10.1093-jac-27.2.5.01964.
Abstract: Aktas Z, 2008, CHEMOTHERAPY, V54, P101, DOI 10.1159-000118661; BROWN DFJ, 1991, J ANTIMICROB CHEMOTH, V27, P185, DOI 10.1093-jac-27.2.185; Carrer A, 2008, ANTIMICROB AGENTS CH, V52, P2950, DOI 10.1128-AAC.01672-07; CARRER A, 2010, ANTIMICROBIAL AGENTS, V54, P1312; Cuzon G, 2008, ANTIMICROB AGENTS CH, V52, P3463, DOI 10.1128-AAC.00543-08; Gulmez D, 2008, INT J ANTIMICROB AG, V31, P523, DOI 10.1016-j.ijantimicag.2008.01.017; Kanj SS, 2008, CLIN MICROBIOL INFEC, V14, P501, DOI 10.1111-j.1469-0691.2008.01964.x; Leavitt A, 2007, ANTIMICROB AGENTS CH, V51, P3026, DOI 10.1128-AAC.00299-07; Matar GM, 2008, CLIN MICROBIOL INFEC, V14, P887, DOI 10.1111-j.1469-0691.2008.02059.x; Naas T, 2003, ANTIMICROB AGENTS CH, V47, P19, DOI 10.1128-AAC.47.1.19-26.2003; Poirel L, 2007, FUTURE MICROBIOL, V2, P501, DOI 10.2217-17460913.2.5.501; 2005, M100S15 CLIN LAB S S
46 citations
TL;DR: A VL map was created and stratified into areas of 'risk' and 'non-risk' for the disease, based on calculations of risk indices, and it was found that the presence of waterbodies, woodland and urban, built-up areas, soil of the fluvisol type, and an annual rainfall were all positively associated with the incidence of VL.
Abstract: Human visceral leishmaniasis (VL) or kala-azar remains a major cause of mortality, particularly in the developing world. The disease is common in the internal regions of north-eastern India, which have a tropical or sub-tropical climate. In a recent study on VL in this region, the relationship between the incidence of VL and certain physio-environmental factors was explored, using a combination of a geographical information system (GIS), satellite imagery and data collected 'on the ground'. Some eco-environmental parameters were then used to map and describe the spatial heterogeneity seen in the transmission of the parasite (Leishmania donovani) that causes VL in India, and to identify those habitats, on the Gangetic plain, where the sandfly vectors might thrive. It was found that the presence of waterbodies, woodland and urban, built-up areas, soil of the fluvisol type, air temperatures of 25.0-27.5 degrees C, relative humidities of 66%-75%, and an annual rainfall of 100-<160 cm were all positively associated with the incidence of VL. A VL map was created and stratified into areas of 'risk' and 'non-risk' for the disease, based on calculations of risk indices.
45 citations
TL;DR: The parasites contributing most to the condemnation of otherwise marketable organs and muscles were E. granulosus and D. dendriticum flukes, which clearly remain too common and cause considerable economic loss in Khorasan and, presumably, other areas of Iran.
Abstract: In nine districts in the north of Khorasan province, in north-eastern Iran, a 5-year retrospective study was carried out to determine the prevalences, in livestock slaughtered in abattoirs, of the parasitic infections responsible for the condemnation of the animals' carcasses and viscera (and the economic importance of such infections in terms of lost meat and offal). Between 20 March 2005 and 19 March 2010, 436,620 animals (45,360 cattle, 275,439 sheep, 115,674 goats and 147 camels) were slaughtered in the study area and the livers of 30,207 (6.9%), the lungs of 23,259 (5.3%) and the carcasses of 1072 (0.2%) of these animals were condemned. Almost all (92.4%) of the condemned livers, most (68.9%) of the condemned lungs but only 10.8% of the condemned carcasses were rejected because of parasitic infection. The parasitic lesions observed in the condemned livers were attributed to Echinococcus granulosus, Fasciola hepatica and/or Dicrocoelium dendriticum (cattle, sheep and goats) or entirely to E. granulosus (camels). All the parasitic lesions observed in the condemned lungs (which also came from cattle, sheep, goats and camels) were attributed to E. granulosus. Sarcocystis cysts and/or Taenia cysticerci were found in ovine muscle while only Taenia cysticerci were detected in bovine muscle (no parasitic lesions were observed in the muscles of the goats and camels). Parasites were responsible for 80.8% of the condemned organs or carcasses, and the value of the food lost because of parasite-related condemnation (based on market prices in 2010) was estimated to be U.S.$421,826 (U.S.$47,980 for cattle, U.S.$316,344.0 for sheep, U.S.$57,372 for goats and U.S.$130 for camels). The parasites contributing most to the condemnation of otherwise marketable organs and muscles were E. granulosus (52.2%) and D. dendriticum flukes (29.5%). These parasites clearly remain too common and cause considerable economic loss in Khorasan and, presumably, other areas of Iran.
TL;DR: Both human African trypanosomiasis and human visceral leishmaniasis affect the poorest of the poor in endemic countries, cause considerable direct and indirect costs and push affected households deeper into poverty.
Abstract: Several tropical diseases that are essentially poverty-related have recently gained more attention under the label of 'neglected tropical diseases' or NTD. It is estimated that over 1000 million people currently suffer from one or more NTD. Here, the socio-economic aspects of two NTD - human African trypanosomiasis and human visceral leishmaniasis - are reviewed. Both of these diseases affect the poorest of the poor in endemic countries, cause considerable direct and indirect costs (even though the national control programmes tend to provide free care) and push affected households deeper into poverty.
TL;DR: Although the data collected indicated that the transmission of the parasite causing CL was mostly outdoor (and possibly zoonotic) in the north of the country, most of the transmission in the south seemed to be peridomestic.
Abstract: Sri Lanka is the newest reported focus of human leishmaniasis within the Indian subcontinent. Over the last 8 years, more than 2000 cases of cutaneous leishmaniasis (CL), apparently caused by Leishmania donovani (a species usually associated with the visceral form of the disease), have been passively identified in the country. The clinical profiles of 401 suspected cases of CL in Sri Lanka were recently explored and some of the cases' immunological responses were investigated, in antibody-detection assays based on the rk39 antigen. These studies were followed by cross-sectional surveys, involving active case detection, in three areas of Sri Lanka, two of them known to be at relatively high risk for CL, with the aims of estimating the local prevalences of the disease and identifying the main risk factors for its acquisition. This appears to be the first detailed report on the prevalence, risk factors and human serological response associated with human leishmaniasis in Sri Lanka.Although the data ...
TL;DR: The developed PCR assays could provide useful tools for the detection, identification and epidemiological investigation of Fasciola infection in humans, other mammals and snails.
Abstract: Among the helminths infecting ruminants in China are three taxa belonging to the genus Fasciola: F. hepatica, F. gigantica and the so-called 'intermediate form' that appears to lie between these two species. Based on the sequences of the second internal-transcribed spacers (ITS-2) within the parasites' nuclear ribosomal DNA (rDNA), a pair of primers (DSJf/DSJ3) specific for F. hepatica and a pair (DSJf/DSJ4) specific for F. gigantica were designed and used to develop PCR-based assays. These assays allowed the identification and differentiation of F. hepatica, F. gigantica and the 'intermediate' Fasciola, with no amplicons produced from heterologous DNA samples. The results of sequencing confirmed the species-specific identity of the amplified products. The assays showed good sensitivity, giving positive results with as little as 0.11 ng of F. hepatica DNA and 0.35 ng of F. gigantica DNA. This meant that the DNA from a single Fasciola egg or a single infected snail was sufficient for identification of the Fasciola taxon. The developed PCR assays could provide useful tools for the detection, identification and epidemiological investigation of Fasciola infection in humans, other mammals and snails.
TL;DR: If PEC is to become adequately grounded in Africa, the generation of further evidence of the effectiveness and limitations of such care would be a prudent move.
Abstract: The models for addressing the delivery of an eye-care service in sub-Saharan Africa have seen considerable revision in the last 30 years, and the on-going challenges, as well as the future needs, will probably require many more changes and new systems. There is a need to assess the different models that are currently employed, in order to ensure that all potential contributions to the elimination of avoidable blindness are used; the evolving concept of primary eye care (PEC) requires such assessment. For the current review, the published literature on eye care provided by general front-line healthworkers was screened for articles that provided evidence of the impact of such PEC on the general delivery of eye care in sub-Saharan Africa. Of the 103 relevant articles detected, only three provided evidence of the effectiveness of PEC and the authors of all three of these articles suggested that such eye care was not meeting the needs or expectations of the target populations, the trainers, or programmes of eye care. Among the main problems identified were a lack of a clear definition of the scope of practice for PEC, the need for clarifying the specific skills that a front-line healthworker could perform correctly, and the changing needs and expectations for the delivery of an eye-care service in Africa. If PEC is to become adequately grounded in Africa, the generation of further evidence of the effectiveness and limitations of such care would be a prudent move.
TL;DR: An essential oil extracted from the leaves and flowers of yarrow and tested for in-vitro activity against Leishmania amazonensis and murine macrophages revealed that the oil caused morphological changes in the treated parasites, including alterations in their shape and size.
Abstract: An essential oil was recently extracted from the leaves and flowers of yarrow (Achillea millefolium) and tested for in-vitro activity against Leishmania amazonensis and murine macrophages (i.e. the J774G8 cell line). The median inhibitory concentration (IC(50)) against L. amazonensis promastigotes was 7.8 μg/ml whereas the survival of amastigotes of this pathogen, within peritoneal murine macrophages, was halved by treatment with the oil at 6.5 μg/ml. The mean value for the median cytotoxic concentration of the oil, measured against adherent (uninfected) J774G8 macrophages, was 72.0 μg/ml (i.e. 9.2 and 11.0 times higher, respectively, than the IC(50) against the promastigotes and intracellular amastigotes). Scanning electron microscopy revealed that the oil caused morphological changes in the treated parasites, including alterations in their shape and size. In transmission electron microscopy, promastigotes treated with the oil (at the IC(50) of 7.8 μg/ml) showed various ultrastructural alterations, including changes in the flagellar membrane, abnormal membrane structures, rupture of the plasma membrane, atypical vacuoles, myelin-like figures, and vesicles that resembled autophagic vacuoles.
TL;DR: Soil samples collected below bedsteads or hammocks or from the indoor resting places of dogs were significantly more likely to be positive than the indoor samples collected at other sites, and it seems likely that, in resource-poor settings in Brazil, most transmission of T. penetrans occurs indoors.
Abstract: To explore the local transmission dynamics of Tunga penetrans in Brazil, 134 soil samples from various environments were collected in three different endemic regions of the country and checked for the presence of the flea's larvae, pupae and adults. The samples, which came from an urban slum in the north-east, a village of Xavante indians in the central-west and a community of Yanomami indians living in traditional longhouses (malocas) in the north, were categorized as indoor, outdoor or indoor-outdoor (the latter representing samples collected in the malocas). The proportion of samples found positive for T. penetrans was lowest in the slum (9.3%) and highest in the Yanomami village (32.0%; P=0.01). Soil samples collected below bedsteads or hammocks or from the indoor resting places of dogs were significantly more likely to be positive than the indoor samples collected at other sites (65.0% v. 35.0%; P=0.02). There was no evidence indicating that the presence of T. penetrans in a soil sample was markedly affected by soil temperature, air temperature or air humidity. As no life stages of T. penetrans were found in any outdoor sample, it seems likely that, in resource-poor settings in Brazil, most transmission of T. penetrans occurs indoors. Control measures against the off-host life stages of T. penetrans should therefore be targeted at particular indoor micro-environments.
TL;DR: Using the real-time PCR, E. histolytica DNA was detected in faecal samples from only 10 of the immigrants, with E. dispar DNA detected in the samples from another 117 (90.0%) of the subjects.
Abstract: In an effort to improve the diagnosis of intestinal amoebiasis, a real-time PCR has been used for the detection and differentiation of Entamoeba histolytica and E. dispar infections in African or South American immigrants who live in Spain. Faecal samples from all of the 130 subjects had apparently been found to contain E. histolytica/E. dispar cysts by microscopical examination. Using the real-time PCR, E. histolytica DNA was detected in faecal samples from only 10 (7.7%) of the immigrants, with E. dispar DNA detected in the samples from another 117 (90.0%) of the subjects. The use of such PCR in the routine investigation of patients found positive for E. histolytica/E. dispar cysts (by microscopy) is recommended, especially in non-endemic areas.
TL;DR: Samples were taken from the skin lesions of 40 cases of CL patients in the district of Jahrom, so that the causative parasites could be identified, to species, in a nested PCR.
Abstract: Human cutaneous leishmaniasis (CL) is endemic in several parts of Iran, and there is an urban focus of the disease in the district of Jahrom, which forms part of the southern province of Fars. To explore the current profile of the disease in Jahrom district, samples were taken from the skin lesions of 40 cases of CL patients in the district, so that the causative parasites could be identified, to species, in a nested PCR. Although Leishmania tropica has been identified, in the past, as the cause of most of the urban CL in Fars province, the predominant species represented in the recent samples from Jahrom district was L. major (87.5%), while L. tropica was relatively rare (12.5%). More than one in every three (35%) of the cases examined was a child aged 25 such lesions. The change in the predominant parasite causing CL in Jahrom district, from the L. tropica usually associated with the urban disease in Iran to the L. major more usually associated with CL in rural settings, may well necessitate changes in the local strategies for the prevention and control of CL.
TL;DR: This article reviews some of the pertinent and representative applications of GIS, including the use of such systems and remote sensing for the mapping of Chagas disease and human helminthiases, the use in vaccine trials, and the global applications ofGIS for health-information management, disease epidemiology, and pandemic planning.
Abstract: In terms of their applicability to the field of tropical medicine, geographical information systems (GIS) have developed enormously in the last two decades. This article reviews some of the pertinent and representative applications of GIS, including the use of such systems and remote sensing for the mapping of Chagas disease and human helminthiases, the use of GIS in vaccine trials, and the global applications of GIS for health-information management, disease epidemiology, and pandemic planning. The future use of GIS as a decision-making tool and some barriers to the widespread implementation of such systems in developing settings are also discussed.
TL;DR: Phytochemical investigation of an ethyl-acetate extract of the stem bark of Markhamia tomentosa (Bignoniaceae), which had good antimalarial activity in vitro, resulted in the isolation of eight known compounds.
Abstract: Phytochemical investigation of an ethyl-acetate extract of the stem bark of Markhamia tomentosa (Bignoniaceae), which had good antimalarial activity in vitro, resulted in the isolation of eight known compounds: 2-acetylnaphtho[2,3-b]furan-4,9-dione (1), 2-acetyl-6-methoxynaphtho[2,3-b]furan-4,9-dione (2), oleanolic acid (3), pomolic acid (4), 3-acetylpomolic acid (5), tormentic acid (6), beta-sitosterol (7) and beta-sitosterol-3-O-beta-D-glucopyranoside (8). The structures of these compounds were established by spectroscopic methods. Each of compounds 1, 2, 4 and 5 was evaluated in vitro for its antiprotozoal activities against the ring stages of two chloroquine-resistant strains of Plasmodium falciparum (K1 and W2), the amastigotes of Leishmania donovani, and the bloodstream trypomastigotes of Trypanosoma brucei rhodesiense (the species responsible for human malaria, visceral leishmaniasis and African trypanosomiasis, respectively). Although compounds 1 and 2 exhibited potent antiprotozoal activities, they also showed high toxicity against a mammalian (L-6) cell line.
TL;DR: The trends, threats and challenges that face the management of mosquito-borne disease in Australia, including West Nile, chikungunya and Rift Valley fever viruses, and the introduction of exotic vectors, are discussed.
Abstract: Mosquito-borne diseases continue to be a serious public-health concern in Australia. Endemic alphaviruses (including Ross River and Barmah Forest viruses) account for the majority of the arboviral notifications, while some flaviviruses (Murray Valley encephalitis, Japanese encephalitis and Kunjin viruses) cause occasional outbreaks of encephalitis. Dengue epidemics are increasing in frequency in northern Queensland, with the largest outbreak in 50 years occurring during the 2008-2009 wet season. Of great concern are the threats posed by the importation of exotic arboviruses, such as West Nile, chikungunya and Rift Valley fever viruses, the introduction of exotic vectors, and the potential range expansion of key Australian vectors. Environmental and anthropogenic influences provide additional uncertainty regarding the future impact of mosquito-borne pathogens in Australia. This review discusses the trends, threats and challenges that face the management of mosquito-borne disease in Australia. Topical mosquito-borne pathogens of biosecurity and public-health concern, and the potential impacts of environmental and global trends, are discussed. Finally, a short overview of the public-health response capability in Australia is provided.
TL;DR: The distribution of potential vectors along the two transects, according to altitude and bioclimate, was explored.
Abstract: Since the 1970s, Azilal and Ouarzazat have been the main foci for human cutaneous leishmaniasis (CL) in Morocco. The sandflies along the main roads linking these two foci to Marrakech city, which is considered to be an area at risk of CL, were recently surveyed. Among the 872 sandflies collected, in June 2005, on the Marrakech–Ouarzazat road, Sergentomyia fallax was the most common species (36.1%), followed by Phlebotomus sergenti (21.1%), P. papatasi (14.2%), S. minuta (11.7%), P. longicuspis (5.5%), P. alexandri (5.4%), P. perniciosus (4.1%), P. ariasi (0.9%), S. africana (0.6%) and S. dreyfussi (0.3%). On the Marrakech–Azilal road, however, S. minuta was by far the most prevalent species (63.5% of the 1983 sandflies that were collected in August 2006), followed by S. fallax (12.9%), P. perniciosus (12.4%), P. sergenti (4.0%), P. longicuspis (3.0%), P. papatasi (2.8%), S. dreyfussi (1.1%) and P. alexandri (0.2%). The distribution of potential vectors along the two transects, according to altitud...
TL;DR: It appears that intestinal helminthiasis may play a causal or contributory role in the occurrence of childhood malnutrition, at least in the present study area.
Abstract: In January-March 2000, the impact of intestinal helminthiases on the nutritional status of 749 pupils (353 boys and 396 girls) attending public primary schools in the Ife Central local government area of Osun state, in south-western Nigeria, was investigated. Demographic, socio-economic and other relevant information was collected on the pupils, on the same day that a single stool sample was collected from each subject and examined, using Stoll's dilution egg-count technique. The weights, heights and ages of the subjects were recorded and converted to percentages of the reference medians for weight-for-height, weight-for-age and height-for-age. The overall prevalences of helminth infection detected among the 465 malnourished pupils (i.e. those with any form of under-nutrition) and the 284 well-nourished pupils were 32.9% and 25.4%, respectively (P=0.029). The nutritional indices of the pupils who were found helminth-infected were generally lower than those of the pupils who appeared free of intestinal helminths. The mean values for weight-for-height, for example, were higher in the apparently uninfected pupils than in those found infected with any intestinal helminth (P=0.02) or only with Ascaris lumbricoides (P=0.05). Similarly, the mean height-for-age of the pupils who were apparently uninfected was higher than the corresponding value for the pupils found hookworm-positive (P=0.003). The pupils who were each found infected with two or more species of intestinal infection had significantly lower weights-for-heights, weights-for-ages and heights-for-ages than the pupils who appeared to be helminth-free. The results of a multivariate logistic-regression analysis indicated that hookworm infection was a significant risk factor for underweight (P=0.015), wasting (P=0.033) and stunting (P=0.015) whereas Trichuris was only a significant risk factor for stunting (P=0.025). It appears that intestinal helminthiasis may play a causal or contributory role in the occurrence of childhood malnutrition, at least in the present study area. Steps should be taken to control both of these important health problems, through functional school-health programmes that provide regular deworming, supervised school meals and health education.
TL;DR: The first report indicating a positive association between E. histolytica infection and HIV in South Africa is indicated, using an ELISA for the detection of antibodies reacting with the parasite's galactose/–acetyl-D-galactosamine(Gal/GalNAc)-inhibitable adherence lectin.
Abstract: In a recent study in northern South Africa, the seroprevalence of Entamoeba histolytica infection among 257 HIV-positive and 117 HIV-negative individuals was determined, using an ELISA for the detection of antibodies reacting with the parasite's galactose/-acetyl-D-galactosamine(Gal/GalNAc)-inhibitable adherence lectin. Overall, 34.0% of the 374 participants (36.1% of the females and 28.1% of the males) were found seropositive for E. histolytica. Although all age-groups were affected by the amoebic pathogen, the subjects aged 50-59 years had the highest seroprevalence (69.2%). The seroprevalence of E. histolytica was also significantly higher among the HIV-positive subjects than among the HIV-negative (42.8% v. 14.5%; chi(2)=28.65; P<0.0001). Among the HIV-positive subjects, those with fewer than 200 CD4+ cells/microl were relatively more likely to be seropositive for E. histolytica (60.3% v. 43.8%; chi(2)=4.016; P=0.045). This is the first report indicating a positive association between E. histolytica infection and HIV in South Africa. Further studies, for example to determine the occurrence of diarrhoea or liver abscess in the study area, in relation to seropositivity for E. histolytica and/or HIV, are now needed.
TL;DR: Clinicians' understanding of how the epidemiology of the 'non-falciparum' malarias, the biology of the parasites involved, the chemotherapeutic strategies that are available and the problems of emerging drug resistance and changing clinical syndromes are increased.
Abstract: Plasmodium vivax, P. ovale, P. malariae and P. falciparum routinely infect humans. The infections caused by these parasites are loosely referred to as vivax (or benign tertian), ovale, malariae (or quartan) and falciparum (or malignant tertian) malaria, respectively. Recently, P. knowlesi, a parasite of macaque monkeys in South–east Asia, has been identified as the cause of uncomplicated and severe human malaria in Malaysian Borneo. The prescription of appropriate therapies for reliably diagnosed malaria requires a grasp of the epidemiology of the 'non-falciparum' malarias, the biology of the parasites involved, the chemotherapeutic strategies that are available and the problems of emerging drug resistance and changing clinical syndromes. This review is intended to increase clinicians' understanding of how these factors relate to the selection of the antimalarial drugs to be given to a case of 'non-falciparum' malaria, with the aims of improving outcomes and preventing relapses and recrudescences.
TL;DR: The delineation of diagnostic methods for the disease and the challenges that this disease presents for both the clinician and diagnostic laboratory should furnish clinicians with an updated tool to help overcome a number of problems associated with the diagnosis.
Abstract: Human leptospirosis is a zoonotic disease of global importance that causes significant morbidity and mortality, particularly in developing nations. In this review, the history, epidemiology, transmission, clinical presentation and treatment of this disease, and its impact in Australia, are discussed. Central to this review is the delineation of diagnostic methods for the disease and the challenges that this disease presents for both the clinician and diagnostic laboratory. This information should furnish clinicians with an updated tool to help overcome a number of problems associated with the diagnosis of leptospirosis.
TL;DR: These results provide unambiguous evidence of the presence of both An.
Abstract: The Anopheles philippinensis and An. nivipes mosquitoes that form part of the An. annularis species group are morphologically very similar and difficult to differentiate as adults. In consequence, researchers generally refer to all field-collected individuals of these species simply as the An. philippinensis-nivipes species complex. Although this species complex is understood to play a role in the transmission of parasites causing human malaria in north-eastern India, the identity of the exact species involved, and the relative importance of the local An. philippinensis and An. nivipes, are far from clear. To settle this issue, house-frequenting female adults of the An. philippinensis-nivipes species complex were collected from 23 localities in the six north-eastern states, identified to species (using an allele-specific PCR to explore the insects' ribosomal-DNA internal-transcribed-spacer-2 sequences) and checked for Plasmodium DNA (using a nested PCR based on the 18S subunit of the parasite's ribosomal DNA). Of the 337 females of the An. philippinensis-nivipes species complex that were investigated, 275 were identified as An. nivipes and 62 as An. philippinensis. Malarial infection was detected in the heads/thoraces of just two specimens, with P. falciparum DNA detected in one An. nivipes from Nagaland state and one An. nivipes from Assam state. These results provide unambiguous evidence of the presence of both An. philippinensis and An. nivipes in the north-eastern region of India and the involvement of An. nivipes in transmitting P. falciparum in this area.
TL;DR: Establishment of the Snake Park clinic appears to have improved access to snakebite treatment, with cases of snakebite travelling long distances to reach the clinic (because of the lack of any other source of antivenom in Tanzania).
Abstract: In Tanzania, the impact, on clinical outcomes and treatment-seeking behaviour, of a rural, nurse-led clinic that provides free, antivenom-based treatment of snakebite envenomation was recently assessed. Data on all 85 patients who, between April 2007 and the end of 2009, received treatment for snakebite envenomation at the Snake Park clinic in Meserani, Tanzania, were collected prospectively. Although only four cases of snakebite envenomation were treated in the last 9 months of 2007, 34 such cases were treated in 2008 and 47 in 2009. The 85 snakebite cases had a mean age of 23 years and a male:female ratio of 1.4. Most of the bites occurred in the evening or at night and most also occurred during the rainy season. In some cases, the seeking of treatment from traditional healers delayed treatment at the clinic. After being bitten, the snakebite cases travelled a mean of 82 km (range=2-550 km) to reach the clinic. Thirty-two (37%) of the cases were each unable to identify the snake that had bit them. Of the bites in which the snake was identified, the puff adder (Bitis arietans) caused more (24) than any other snake. Forty-two of the snakebite cases received antivenom. Only one patient (1%), a 12-year-old girl, was believed to have died as the result of a snakebite but another six (7%) each required a skin graft or the amputation of a limb or digit. Establishment of the Snake Park clinic appears to have improved access to snakebite treatment, with cases of snakebite travelling long distances to reach the clinic (because of the lack of any other source of antivenom in Tanzania). Although the clinic is nurse-led, treatment outcomes among the snakebite victims who attend the clinic appear to be good.
TL;DR: Ciguatera poisoning is a food-borne neuro-intoxication caused by consumption of finfish that have accumulated ciguatoxins in their tissues, and there is neither a confirmatory diagnostic test nor a reliable, low-cost screening method to ascertain the safety of suspect fish prior to consumption.
Abstract: Ciguatera poisoning is a food-borne neuro-intoxication caused by consumption of finfish that have accumulated ciguatoxins in their tissues. Ciguatera is a distressing and sometimes disabling condition that presents with a self-limiting though occasionally severe gastro-intestinal illness, progressing to a suite of aberrant sensory symptoms. Recovery can take from days to years; second and subsequent attacks may manifest in a more severe illness. Ciguatera remains largely a pan-tropical disease, although tourism and export fish markets facilitate increased presentation in temperate latitudes. While ciguatera poisoning in the South Pacific was recognised and eloquently described by seafarers in the 18th Century, it remains a public-health challenge in the 21st Century because there is neither a confirmatory diagnostic test nor a reliable, low-cost screening method to ascertain the safety of suspect fish prior to consumption. A specific antidote is not available, so treatment is largely supportive. The most promising pharmacotherapy of recent decades, intravenous mannitol, has experienced a relative decline in acceptance after a randomized, double-blind trial failed to confirm its efficacy. Some questions remain unanswered, however, and the use of mannitol for the treatment of acute ciguatera poisoning arguably deserves revisiting. The immunotoxicology of ciguatera is poorly understood, and some aspects of the epidemiology and symptomatology of ciguatera warrant further enquiry.