Moemenbellah-Fard MD, Benafshi O, Rafinejad J
… +1 more, Ashraf H
Ann Trop Med Parasitol
· 2009 Sep · PMID 19695158
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Tick-borne relapsing fever (TBRF) is a neglected zoonotic disease caused by infection with spirochaetes of the genus Borrelia. Humans usually contract it from the bite of infected soft ticks of the genus Ornithodoros. In...Tick-borne relapsing fever (TBRF) is a neglected zoonotic disease caused by infection with spirochaetes of the genus Borrelia. Humans usually contract it from the bite of infected soft ticks of the genus Ornithodoros. In Iran, where the disease is endemic in the mountainous north-western provinces, reports of over 200 cases annually probably under-estimate the true incidence. The species, distribution and infection of ticks that are potential vectors of Borrelia and the clinical and epidemiological characteristics of the local TBRF cases were recently investigated in the villages in and around the county town of Bijar, in north-western Iran. A blood sample from each suspected case of TBRF was checked for B. persica by dark-field microscopy, data were collected on the demographics and clinical manifestations of each confirmed case, and the prevalence of tick infection with borreliae and the monthly incidence of TBRF were evaluated. Between 2000 and 2007, 148 cases of TBRF (each with fever, chills and headache) were passively detected in the town. Most (115) of these were confirmed by microscopy, with the other subjects categorized as probable (21) or suspected cases (12) of TBRF. Most (91%) of the 148 subjects were young people, and most came from rural areas and lived in large households in the old mud-and-thatch houses of Bijar. Most (82%) of the cases occurred during the summer or early autumn. Overall, 8543 soft ticks (Ornithodoros tholozani, O. lahorensis, Argas persicus and A. reflexus) were collected by clustered random sampling. When a random sample of the O. tholozani ticks (96 of the 577 collected) was checked for B. persica infection, by being crushed and then inoculated intraperitoneally into a mouse or suckling Syrian hamster, 19 were found infected. Peaks in the monthly incidence of TBRF occurred as the numbers of O. tholozani in the tick collections peaked, and it seems likely that most of the cases were caused by B. persica transmitted by O. tholozani. Further studies in Iran, to map the geographical variation in the prevalence of soft-tick infection with Borrelia and identify any Borrelia reservoirs, are recommended.
Magoni M, Ekra KD, Aka LN
… +2 more, Sita KS, Kanga K
Ann Trop Med Parasitol
· 2009 Sep · PMID 19695157
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Ivory Coast has a high prevalence of infection with hepatitis B virus (HBV). The effects of a control programme based on the anti-HBV vaccine, which has formed part of the national Expanded Programme on Immunization (EPI...Ivory Coast has a high prevalence of infection with hepatitis B virus (HBV). The effects of a control programme based on the anti-HBV vaccine, which has formed part of the national Expanded Programme on Immunization (EPI) since 2000, have recently been evaluated in the country, for the first time. In this, cross-sectional investigation, two-stage cluster sampling stratified by age was used to assess the impact of the programme of universal childhood HBV vaccination in the Grand Bassam health district. The seroprevalences of carriage of the HBV surface antigen (HBsAg) and of antibodies to this antigen (HBsAb) and to the core antigen of HBV (HBcAb) were estimated among children aged 12-59 months and their mothers. Serology was successful for 1038 children (of 1172 in the original sample) and 836 mothers. Of the children enrolled, 46.8% had had a standard vaccination (completed before the age of 6 months, with the correct schedule), 4.6% had had no vaccination against HBV, and the rest had received incomplete or incorrectly timed vaccination. The prevalence of HBsAg carriage was 0.7% among the tested children and 9.9% among the tested mothers. The prevalence of seroprotection (i.e. an HBsAb titre of >10 mIU/ml), which was 74.2% overall, was strongly correlated with the number of vaccination doses, ranging from 16.7% in the unvaccinated infants to 85.5% in the children who had each received four doses. Circulation of the virus (indicated by seropositivity for HBcAb) was much higher among the unvaccinated children (10.4%) than the fully vaccinated ones (2.9%). The prevalences of both HBsAg and HBcAb were higher in rural areas, where vaccine coverage was relatively low, than in the urban areas. It appears that HBV vaccine is highly effective within the framework of the EPI in Ivory Coast, where it has already had a positive impact in reducing HBsAg carriage among children under 5 years of age. Improving vaccination coverage in the rural areas of the country is now a public-health priority.
Kim EM, Verweij JJ, Jalili A
… +5 more, van Lieshout L, Choi MH, Bae YM, Lim MK, Hong ST
Ann Trop Med Parasitol
· 2009 Sep · PMID 19695156
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Human clonorchiasis, caused by infection with the trematode Clonorchis sinensis, is a common health problem in East Asia. In an attempt to develop a new, sensitive method for the diagnosis of the disease, the use of a re...Human clonorchiasis, caused by infection with the trematode Clonorchis sinensis, is a common health problem in East Asia. In an attempt to develop a new, sensitive method for the diagnosis of the disease, the use of a real-time PCR (targeting the internal-transcribed-spacer-2 sequence of the parasite) to detect C. sinensis-specific DNA in faecal samples has recently been evaluated. The PCR-based assay, which included an internal control to detect any inhibition of the amplification by faecal constituents in the sample, was performed on stool samples and on DNA controls representing a wide range of intestinal microorganisms. The assay appeared very specific, only showing positivity with C. sinensis and Opisthorchis felineus. The sensitivity of the assay was explored by testing 170 preselected samples of human faeces, from an endemic area of South Korea, which had known (microscopically-determined) densities of C. sinensis eggs. The sensitivity of the assay was 100% for the 74 samples that each had > 100 eggs/g and 91.4% for the other 70 samples found egg-positive by microcopy (i.e. those that had <or= 100 eggs/g). Three of the 26 samples that appeared egg-negative by microscopy were found PCR-positive. Encouragingly, the PCR cycle-threshold values, which reflect parasite-specific DNA loads, showed significant correlation with the egg counts. The real-time PCR used in this study therefore appears to be a powerful tool for both the detection and quantification of C. sinensis infections.
Gutman J, Richards FO, Eigege A
… +3 more, Umaru J, Alphonsus K, Miri ES
Ann Trop Med Parasitol
· 2009 Sep · PMID 19695155
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The results of previous studies in Nigeria indicate that 81% of the villages in Plateau and Nasarawa states probably qualify for the mass administration of praziquantel (PZQ) because of Schistosoma haematobium (SH) and/o...The results of previous studies in Nigeria indicate that 81% of the villages in Plateau and Nasarawa states probably qualify for the mass administration of praziquantel (PZQ) because of Schistosoma haematobium (SH) and/or S. mansoni (SM) infection. To determine the best strategy, relative costs were modelled for four different programmatic approaches to mass drug administration (MDA) at village level. The approaches considered were (1) village-by-village screening for SH (using dipsticks to test for haematuria), with MDA confined to those villages where at least 20% of school-aged children were found infected; (2) screening for both SM (using Kato-Katz smears) and SH, with MDA confined to those villages where at least 20% of school-aged children were found infected with SH or at least 10% of such children were found SM-positive; (3) the presumptive annual treatment of all school-aged children with PZQ (without village-by-village screening); and (4) the presumptive annual treatment of all eligible adults and children with PZQ. In the MDA in models 1 and 2, treatment is only given to children unless the prevalence of schistosome infection is >or=50%, when adults are also treated. As first-year 'assessment' costs were particularly high for the models that included screening, costs were projected over 5 years for all four models. The total 5-year costs, to cover a population of 30,000, were U.S.$18,673 for the model with screening only for SH, U.S.$36,816 for the model with screening for both SH and SM, U.S. $15,510 for the treatment of all school-aged children, and U.S.$68,610 for the treatment of the entire population. Although the presumptive treatment of school-aged children appeared to be the cheapest approach, it would exclude the community-wide treatment of highly endemic communities, the importance of which needs further study.
Kelvin EA, Carpio A, Bagiella E
… +5 more, Leslie D, Leon P, Andrews H, Hauser WA, Ecuadorian Neurocysticercosis Group
Ann Trop Med Parasitol
· 2009 Sep · PMID 19695154
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The results of previous investigations indicate that age and gender may influence the strength of the human host's immune response to infection of the central nervous system with the larvae of Taenia solium. Most of the...The results of previous investigations indicate that age and gender may influence the strength of the human host's immune response to infection of the central nervous system with the larvae of Taenia solium. Most of the relevant research on such neurocysticercosis (NCC) has, however, been conducted on hospital-based samples in developing countries, where differential access to healthcare may bias the study results. Using data from 171 NCC patients participating in a treatment trial, the associations of patient age and gender with the presence of inflammation around NCC cysts (i.e. cysts in the transitional phase) have recently been explored, after controlling for measures of economic and geographical access to healthcare. Data on cysts were collected from computed-tomography or magnetic-resonance images taken at four time-points, from baseline to 12-months post-treatment. The odds of having transitional cysts were evaluated by logistic regression whereas Poisson regression was used to explore the numbers of transitional cysts, with generalised estimating equations (GEE) used to account for the multiple observations over time. After controlling for healthcare access, the odds of having transitional cysts were found to be 1.5-fold higher for the female patients than for the male, although this association was not statistically significant (P = 0.136). In the Poisson model, however, the number of transitional cysts was found to be 1.8-fold higher in the female patients than in the male, and this gender effect was not only statistically significant (P = 0.002) but also constant over time. The association of host age with transitional cysts was more complicated, with significant interaction between age and time. It therefore appears that there are significant gender and age differences in the local immune response to NCC, even after adjusting for differences in healthcare access.
Ann Trop Med Parasitol
· 2009 Sep · PMID 19695153
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Between May 2006 and March 2007, 65 water samples were collected from both heated and unheated swimming pools in the city of Porto Alegre, the capital of the Brazilian state of Rio Grande do Sul. The aim was to explore t...Between May 2006 and March 2007, 65 water samples were collected from both heated and unheated swimming pools in the city of Porto Alegre, the capital of the Brazilian state of Rio Grande do Sul. The aim was to explore the problem posed by, and the pathogenic potential of, Acanthamoeba in the pools. Free-living amoebae in the samples were isolated by culture with Escherichia coli and identified from trophozoite and cyst morphology and the results of a PCR with Acanthamoeba-specific oligonucleotide primers. Potential pathogenicity was assessed in osmotolerance and thermotolerance assays. Thirteen (20%) of the water samples investigated were found positive for free-living amoebae, all identified as belonging to morphological groups II (nine isolates) or III (four isolates) of the genus Acanthamoeba. All 13 isolates were found positive in the Acanthamoeba-specific PCR, and the results of the tolerance assays indicated that five (38%) of the isolates should be considered potentially pathogenic. The results of this first study on the occurrence and distribution of Acanthamoeba in the water of swimming pools in Porto Alegre confirm the presence of potentially pathogenic types that may present a risk to human health.
de Almeida EA, Silva EL, Guariento ME
… +2 more, Aoki FH, Pedro Rde J
Ann Trop Med Parasitol
· 2009 Sep · PMID 19695152
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Two Brazilian cases of Trypanosoma cruzi/HIV co-infection have recently been treated with azole derivatives. Benznidazole, the drug generally used for the treatment of Chagas disease, was initially used in one case but d...Two Brazilian cases of Trypanosoma cruzi/HIV co-infection have recently been treated with azole derivatives. Benznidazole, the drug generally used for the treatment of Chagas disease, was initially used in one case but discontinued because of an adverse effect (retrobulbar neuritis) and replaced by itraconazole. The other case had oesophageal candidiasis, which was treated with ketoconazole, a drug that had already been shown to be effective in the treatment of Chagas disease. Since the medications were effective in reducing the T. cruzi parasitaemia in both patients, they probably helped prevent the severe morbidity sometimes associated with Chagas disease, although the HIV infections still proved fatal in both cases.
Ishengoma DR, Rwegoshora RT, Mdira KY
… +5 more, Kamugisha ML, Anga EO, Bygbjerg IC, Rønn AM, Magesa SM
Ann Trop Med Parasitol
· 2009 Jul · PMID 19583914
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Although critical for good case management and the monitoring of health interventions, the health-laboratory services in sub-Saharan Africa are grossly compromised by poor infrastructures and a lack of trained personnel,...Although critical for good case management and the monitoring of health interventions, the health-laboratory services in sub-Saharan Africa are grossly compromised by poor infrastructures and a lack of trained personnel, essential reagents and other supplies. The availability and quality of diagnostic services in 37 health laboratories in three districts of the Tanga region of Tanzania have recently been assessed. The results of the survey, which involved interviews with health workers, observations and a documentary review, revealed that malaria accounted for >50% of admissions and out-patient visits. Most (92%) of the laboratories were carrying out malaria diagnosis and 89% were measuring haemoglobin concentrations but only one (3%) was conducting culture and sensitivity tests, and those only on urine and pus samples. Only 14 (17%) of the 84 people found working in the visited laboratories were laboratory technologists with a diploma certificate or higher qualification. Sixteen (43%) of the study laboratories each had five or fewer types of equipment and only seven (19%) had more than 11 types each. Although 11 (30%) of the laboratories reported that they conducted internal quality control, none had standard operating procedures (SOP) on display or evidence of such quality assurance. Although malaria was the main health problem, diagnostic services for malaria and other diseases were inadequate and of poor quality because of the limited human resources, poor equipment and shortage of supplies. If the health services in Tanga are not to be overwhelmed by the progressively increasing burden of HIV/AIDS, malaria, tuberculosis and other emerging and re-emerging diseases, more funding and appropriate policies to improve the availability and quality of the area's diagnostic services will clearly be required.
Ann Trop Med Parasitol
· 2009 Jul · PMID 19583913
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In a recent study, various extracts of Pterocarpus angolensis were prepared and tested against bacteria. The acetone extract was found to be the most active against all the bacteria investigated, with minimum inhibitory...In a recent study, various extracts of Pterocarpus angolensis were prepared and tested against bacteria. The acetone extract was found to be the most active against all the bacteria investigated, with minimum inhibitory concentrations varying from 0.0156 mg/ml against Staphylococcus aureus to 2 mg/ml against Enterobacter cloacae. Seven pure compounds were subsequently isolated from the ethanol extract of P. angolensis. Using several chromatographic and spectroscopic methods, the structures of five of these compounds - phthalate and four derivatives of epicatechin [(-)-epicatechin, epicatechin-3-O-galate, epicatechin (4beta-8)-epicatechin (B2), and a hexamer of epicatechin] - were successfully determined. The seven purified compounds were then further tested, in vitro, against Staphylococcus aureus and Entamoeba histolytica, and for their in-vitro cytotoxic activity. Although all seven were active against S. aureus, just one of the purified compounds from P. angolensis and piperitenone, a pure compound isolated from Lippia javanica essential oil, were found to have marked activity against Entamoeba histolytica, with median inhibitory concentrations (IC(50)) of 25 and 100 microg/ml, respectively. The other P. angolensis compounds were either weakly active or showed no activity against the amoebae when tested at concentrations up to 400 microg/ml. All seven compounds isolated from P. angolensis showed less toxicity against cultures of human (HCT-8) cells than piperitenone, with IC(50) of 175-375 microg/ml. The presence of epichatechin and derivatives (with strong antibacterial activities but generally weak activities against Entamoeba histolytica) in the stem bark of P. angolensis has thus been demonstrated. Further investigation of the activities of these compounds and their potential use in the treatment of bacterial diseases appears justified.
Ogrzewalska M, Pacheco RC, Uezu A
… +3 more, Richtzenhain LJ, Ferreira F, Labruna MB
Ann Trop Med Parasitol
· 2009 Jul · PMID 19583912
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The rickettsial infections in 174 Amblyomma nodosum found on passeriform birds in the Atlantic forest, eastern Brazil, have recently been evaluated. Rickettsiae were successfully isolated from two ticks, using cultures o...The rickettsial infections in 174 Amblyomma nodosum found on passeriform birds in the Atlantic forest, eastern Brazil, have recently been evaluated. Rickettsiae were successfully isolated from two ticks, using cultures of Vero cells. Both isolates were molecularly characterised, using the rickettsial genes gltA and htrA and, when possible, also ompA and ompB. Portions of the gltA and htrA genes from one of the rickettsial isolates were found be closely match the corresponding GenBank sequences for Rickettsia bellii, with 99.9% and 100% homology, respectively. This isolate was named R. bellii strain Pontal. Portions of the gltA, htrA and ompB genes from the second isolate most closely matched the corresponding sequences of R. parkeri, whereas a portion of the ompA gene from this isolate was closest to the relevant sequence of Rickettsia sp. strain COOPERI (which has been considered to be a strain of R. parkeri in Brazil). The second isolate was named R. parkeri strain NOD. Further investigation of the 172 ticks from which isolates were not recovered revealed R. parkeri strain NOD in 40 and R. bellii strain Pontal in nine, giving overall infection prevalences of 23.6% (41/174) and 5.7% (10/174), respectively. This appears to be the first report of R. bellii and R. parkeri in A. nodosum.
Marcotty T, Matthys F, Godfroid J
… +24 more, Rigouts L, Ameni G, Gey van Pittius N, Kazwala R, Muma J, van Helden P, Walravens K, de Klerk LM, Geoghegan C, Mbotha D, Otte M, Amenu K, Abu Samra N, Botha C, Ekron M, Jenkins A, Jori F, Kriek N, McCrindle C, Michel A, Morar D, Roger F, Thys E, van den Bossche P
Ann Trop Med Parasitol
· 2009 Jul · PMID 19583911
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Late in 2007, veterinary, medical and anthropological professionals from Europe and Africa met in a 2-day workshop in Pretoria, South Africa, to evaluate the burden, surveillance and control of zoonotic tuberculosis and...Late in 2007, veterinary, medical and anthropological professionals from Europe and Africa met in a 2-day workshop in Pretoria, South Africa, to evaluate the burden, surveillance and control of zoonotic tuberculosis and brucellosis in sub-Saharan Africa. Keynote presentations reviewed the burden of these diseases on human and livestock health, the existing diagnostic tools, and the available control methods. These presentations were followed by group discussions and the formulation of recommendations. The presence of Mycobacterium bovis and Brucella spp. in livestock was considered to be a serious threat to public health, since livestock and animal products are the only source of such infections in human beings. The impact of these pathogens on human health appears to be relatively marginal, however, when compared with Mycobacterium tuberculosis infections and drug resistance, HIV and malaria. Appropriate diagnostic tools are needed to improve the detection of M. bovis and Brucella spp. in humans. In livestock, the 'test-and-slaughter' approach and the pasteurization of milk, which have been used successfully in industrialized countries, might not be the optimal control tools in Africa. Control strategies should fit the needs and perceptions of local communities. Improved intersectoral and international collaboration in surveillance, diagnosis and control, and in the education of medical and veterinary personnel, are advocated.
Mosleh IM, Geith E, Schönian G
… +1 more, Kanani KA
Ann Trop Med Parasitol
· 2009 Jul · PMID 19583910
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Two temporally distinct outbreaks of human cutaneous leishmaniasis (CL), as well as scattered cases of the disease, have recently been observed close to the Dead Sea, in Jordan. Each of the two outbreaks, which occurred...Two temporally distinct outbreaks of human cutaneous leishmaniasis (CL), as well as scattered cases of the disease, have recently been observed close to the Dead Sea, in Jordan. Each of the two outbreaks, which occurred in 2004/2005 and 2007/2008, involved a group of foreign workers who were deployed within otherwise uninhabited locations. During each outbreak, about 20% of the workers were found infected with the causative parasite. In the earlier outbreak, 61 workers were found to have skin lesions like those of CL and all but three were confirmed by culture and/or the examination of smears (40 cases) or, in the case of 18 (86%) of the 21 suspected cases found smear- and culture-negative, by PCR. In the second outbreak, the cases were only identified from their clinical manifestations and their response to antileishmanial treatment (cryotherapy). Leishmania major was identified as the cause of the 2004/2005 outbreak and some sporadic cases that occurred, in 2004, along the shores of the Dead Sea. The burrows of potential reservoir hosts were found close to the outbreak locations, frequently under the chenopod Seidlitzia rosmarinus. The two outbreaks emphasise the continuing problem posed by the CL focus in the Mid Jordan Valley and its impact on humans who move into the area. Curiously, an investigation on the socio-economic conditions of the workers during the outbreaks identified a group of 48 workers who were living in air-conditioned rooms during the 2007/2008 outbreak, among whom no CL cases were found. In contrast, 26 of a neighbouring group of 124 workers, who were all living in non-air-conditioned rooms, developed CL lesions. The role of air conditioning, and of other factors and measures, in the prevention of the transmission of the causative parasites of CL merits further investigation and the attention of the local health authorities.
Falade CO, Nash O, Akingbola TS
… +3 more, Michael OS, Olojede F, Ademowo OG
Ann Trop Med Parasitol
· 2009 Jul · PMID 19583909
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The emergence and wide dissemination of drug-resistant malarial parasites underscore the need to prevent post-transfusion malaria. In Nigeria, as in most of sub-Saharan Africa, however, blood donors are not routinely scr...The emergence and wide dissemination of drug-resistant malarial parasites underscore the need to prevent post-transfusion malaria. In Nigeria, as in most of sub-Saharan Africa, however, blood donors are not routinely screened for malarial infection. Recently, 391 consecutive potential blood donors in a malaria-endemic area of south-western Nigeria were each checked for malarial parasitaemia using three methods: microscopy (all samples), OptiMAL (315 samples) and/or the Clinotech Malaria Cassette (142 samples). OptiMAL detects parasite-specific lactate dehydrogenase whereas the Clinotech test detects the surface proteins of merozoites and sporozoites. Microscopy revealed parasitaemias in 79 (20.2%) of the potential donors, the levels of parasitaemia varying from 34 to 6289 asexual parasites/microl (mean=445/microl). The prevalence of malarial parasitaemia, as detected by microscopy, was significantly higher during the rainy season than in the dry season (27.3% v. 5.5%; P<0.0001). There was no significant association between patent parasitaemia and fever (i.e. an axillary temperature > or =37.5 degrees C), blood group, gender or anaemia. The corresponding prevalences of malarial parasitaemia detected using the rapid diagnostic tests were 3.8% (12/315) for OptiMAL and 57.8% (82/142) for the Clinotech. With the results of the microscopy used as the 'gold standard', OptiMAL gave a sensitivity of only 16.0% but a specificity of 98.5%. The corresponding values for the Clinotech tests were 69.2% and 50.0%, respectively. It would clearly be beneficial to include screening for malaria parasitaemia in the routine investigation of potential blood donors in Nigeria, especially during the rainy season, when the risk of transfusion-transmitted malaria appears relatively high.
Ann Trop Med Parasitol
· 2009 Jul · PMID 19583908
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In terms of either research or public-health policy, podoconiosis, a non-infectious form of elephantiasis, has received little attention since the 1980s. The aim of this narrative review is to examine the results of the...In terms of either research or public-health policy, podoconiosis, a non-infectious form of elephantiasis, has received little attention since the 1980s. The aim of this narrative review is to examine the results of the relevant research published in the past 2 years, in the context of the data from earlier investigations. The review concludes by indicating areas in which further investigation is necessary before robust intervention strategies, to reduce the public-health burden posed by podoconiosis, can be devised.