Parasitology Laboratory

Yaoundé, Cameroon

Parasitology Laboratory

Yaoundé, Cameroon

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Al-Herrawy A.,Parasitology Laboratory | Bahgat M.,NRC | Mohammed A.,Ain Shams University | Ashour A.,Ain Shams University | Hikal W.,Parasitology Laboratory
Iranian Journal of Parasitology | Year: 2013

Background: The free-living amoebae Acanthamoeba spp., have been recognized as etiologic agents of amoebic encephalitis, keratitis, otitis, lung lesions and other skin infections mainly in immunocompromised individuals. In this study, morpho-physiological and biochemical characterization of Acanthamoeba strains isolated from the Egyptian aquatic environment were surveyed. Methods: some Acanthamoeba species were cultivated on non-nutrient agar. Isolated strains of Acanthamoeba were identification based on the morphology of trophic and cyst forms in addition to temperature and osmo-tolerance assays. Biochemical characterization of the isolated amoeba strains was performed using quantitative assay as well as qualitative determination of proteolytic activity in zymograph analysis. Results: Potentially pathogenic Acanthamoeba species were isolated from all of the examined water sources. Colorimetric assays showed protease activity in the heattolerant isolates of Acanthamoeba. All pathogenic isolates of Acanthamoeba exhibited higher protease activity than did the non-pathogenic ones. The zymographic protease assays showed various banding patterns for different strains of Acanthamoeba. Conclusion: The incidence and prevalence of the pathogenic Acanthamoeba species in the aquatic environment using parasitological and biochemical diagnostic tools will provide baseline data against which the risk factors associated with waterborne transmission can be identified.


Al-Herrawy A.,Parasitology Laboratory | Bahgat M.,NRC | Mohammed A.-E.,Ain Shams University | Ashour A.,Ain Shams University | Hikal W.,Parasitology Laboratory
Iranian Journal of Parasitology | Year: 2014

Background: The free-living amoebae Acanthamoeba spp. have been recognized as etiologic agents of amoebic encephalitis, keratitis, otitis, lung lesions and other skin infections mainly in immunocompromised individuals. The purpose of this study is to detect the presence of Acanthamoeba in swimming pools in Egypt using a polymerase chain reaction (PCR) method. Methods: Water samples were collected from 10 different swimming pools in Cairo, Egypt. Samples were cultured on nonnutrient agar for the detection of Acanthamoeba isolates that were confirmed by PCR amplification using genus specific primers. The molecularly confirmed Acanthamoeba isolates were morphologically identified to the species level. Results: Members of genus Acanthamoeba were detected in 49.2% of the examined swimmingpool water samples. Morphologically, six Acanthamoeba species were isolated from the examined swimming pool water namely A. polyphaga, A.castellanii, A. rhysodes, A. mauritaniensis, A. royreba and A. triangularis. All the identified species of Acanthamoeba were molecularly confirmed to be related to the genus Acanthamoeba. Conclusion: The isolated species of Acanthamoeba could provoke variable degrees of infections to the swimmers. The culture method is cheaper and easier than PCR techniques that are faster for the detection of freeliving amoebae.


Silveira I.,University of Sao Paulo | Martins T.F.,University of Sao Paulo | Olegario M.M.,Federal University of Uberlandia | Peterka C.,Foundation Medicine | And 3 more authors.
Zoonoses and Public Health | Year: 2015

A previous study in Paulicéia Municipality, south-eastern Brazil, reported 9.7% of the Amblyomma triste ticks to be infected by Rickettsia parkeri, a bacterial pathogen that causes spotted fever in humans. These A. triste ticks were shown to be associated with marsh areas, where the marsh deer Blastocerus dichotomus is a primary host for this tick species. During 2008-2009, blood serum samples were collected from 140 horses, 41 dogs, 5 opossums (Didelphis albiventris) and 26 humans in farms from Pauliceia Municipality. Ticks were collected from these animals, from vegetation and from additional wildlife in these farms. Overall, 25% (35/140) of the horses, 7.3% (3/41) of the dogs, 3.8% (1/26) of the humans and 100% (5/5) of the opossums were seroreactive (titre ≥64) to spotted fever group (SFG) Rickettsia spp. Multivariate statistical analysis indicated that horses that were allowed to forage in the marsh were 4.8 times more likely to be seroreactive to spotted fever group (SFG) Rickettsia spp than horses that did not forage in the marsh. In addition, horses that had been living in the farm for more than 8.5 years were 2.8 times more likely to be seroreactive to SFG Rickettsia spp than horses that were living for ≤8.5 years. Ticks collected from domestic animals or from vegetation included Amblyomma cajennense, Amblyomma coelebs, Amblyomma dubitatum, Dermacentor nitens and Rhipicephalus microplus. By PCR analyses, only one pool of A. coelebs ticks from the vegetation was shown to be infected by rickettsiae, for which DNA sequencing revealed to be Rickettsia amblyommii. Ticks (not tested by PCR) collected from wildlife encompassed A. cajennense and Amblyomma rotundatum on lizards (Tupinambis sp), and A. cajennense and A. triste on the bird Laterallus viridis. Our results indicate that the marsh area of Paulicéia offers risks of infection by SFG rickettsiae. © 2015 Blackwell Verlag GmbH.


Boufana B.,University of Salford | Lahmar S.,Parasitology Laboratory | Rebai W.,University of Tunis | Safta Z.B.,University of Tunis | And 5 more authors.
Transactions of the Royal Society of Tropical Medicine and Hygiene | Year: 2014

Background: The species/genotypes of Echinococcus infecting a range of intermediate, canid and human hosts were examined as well as the intraspecific variation and population structure of Echinococcus granulosus sensu lato (s.l.) within these hosts. Methods: A total of 174 Echinococcus isolates from humans and ungulate intermediate hosts and adult tapeworms from dogs and jackals were used. Genomic DNA was used to amplify a fragment within a mitochondrial gene and a nuclear gene, coding for cytochrome c oxidase subunit 1 (cox1; 828 bp) and elongation factor 1-alpha (ef1a; 656 bp), respectively. Results: E. granulosus sensu strictowas identified fromall host species examined, E. canadensis (G6) in a camel and, for the first time, fertile cysts of E. granulosus (s.s.) and E. equinus in equids (donkeys) and E. granulosus (s.s.) fromwild boars and goats. Considerable genetic variation was seen only for the cox1 sequences of E. granulosus (s.s.). The pairwise fixation index (Fst) for cox1 E. granulosus (s.s.) sequences fromdonkeyswas high andwas statistically significant comparedwith that of E. granulosus populations fromother intermediate hosts. A single haplotype (EqTu01) was identified for the cox1 nucleotide sequences of E. equinus. Conclusions: The role of donkeys in the epidemiology of echinococcosis in Tunisia requires further investigation. © The Author 2014.


Davidson R.K.,Norwegian Veterinary Institute | Romig T.,University of Hohenheim | Jenkins E.,University of Saskatchewan | Tryland M.,Section for Arctic Veterinary Medicine | Robertson L.J.,Parasitology Laboratory
Trends in Parasitology | Year: 2012

In the past three decades, . Echinococcus multilocularis, the cause of human alveolar echinococcosis, has been reported in several new countries both in definitive hosts (canids) as well as in people. Unless treated, infection with this cestode in people is fatal. In previously endemic countries throughout the Northern Hemisphere, geographic ranges and human and animal prevalence levels seem to be increasing. Anthropogenic influences, including increased globalisation of animals and animal products, and altered human/animal interfaces are thought to play a vital role in the global emergence of this pathogenic cestode. Molecular epidemiological techniques are a useful tool for detecting and tracing introductions, and differentiating these from range expansions. © 2012 Elsevier Ltd.


Robertson L.J.,Parasitology Laboratory | Sprong H.,National Institute of Public Health and the Environment | Ortega Y.R.,University of Georgia | van der Giessen J.W.B.,National Institute of Public Health and the Environment | Fayer R.,U.S. Department of Agriculture
Trends in Parasitology | Year: 2014

Globalisation is a manmade phenomenon encompassing the spread and movement of everything, animate and inanimate, material and intangible, around the planet. The intentions of globalisation may be worthy - but may also have unintended consequences. Pathogens may also be spread, enabling their establishment in new niches and exposing new human and animal populations to infection. The plethora of foodborne parasites that could be distributed by globalisation has only recently been acknowledged and will provide challenges for clinicians, veterinarians, diagnosticians, and everyone concerned with food safety. Globalisation may also provide the resources to overcome some of these challenges. It will facilitate sharing of methods and approaches, and establishment of systems and databases that enable control of parasites entering the global food chain. © 2013 Elsevier Ltd.


Davidson R.,Norwegian Veterinary Institute | Simard M.,Makivik Corporation | Kutz S.J.,University of Calgary | Kapel C.M.O.,Copenhagen University | And 2 more authors.
Trends in Parasitology | Year: 2011

The significant impact on human and animal health from parasitic infections in tropical regions is well known, but parasites of medical and veterinary importance are also found in the Arctic. Subsistence hunting and inadequate food inspection can expose people of the Arctic to foodborne parasites. Parasitic infections can influence the health of wildlife populations and thereby food security. The low ecological diversity that characterizes the Arctic imparts vulnerability. In addition, parasitic invasions and altered transmission of endemic parasites are evident and anticipated to continue under current climate changes, manifesting as pathogen range expansion, host switching, and/or disease emergence or reduction. However, Arctic ecosystems can provide useful models for understanding climate-induced shifts in host-parasite ecology in other regions. © 2011 Elsevier Ltd.


Davidson R.K.,Norwegian Veterinary Institute | Robertson L.J.,Parasitology Laboratory
Zoonoses and Public Health | Year: 2012

Inter-country travel of companion animals provides an opportunity for introduction of zoonotic pathogens, such as rabies virus and Echinococcus spp. Regulations are in place to control this threat, but Schengen Agreements mean that border controls between some European countries are minimal, and animals may enter countries without any checks that they have been appropriately treated. Veterinarians provide an important source of information for people intending to travel with their pets. We conducted a telephone survey to investigate provision of correct advice to someone intending to travel with their dog to Norway. Mainland Norway is considered free of both rabies and E. multilocularis and is a signatory to the Schengen Agreement. Ten randomly selected veterinary clinics were surveyed in Austria, Belgium (Wallonia), Finland, France, Germany, Norway, Sweden, Switzerland and United Kingdom. The information provided was scored as correct, incorrect or incomplete. The information provided by secondary information sources (website or government agency), which the clinic had referred the caller to, was also assessed (correct, incorrect, incomplete). Whilst the majority of clinics provided appropriate information regarding rabies, many clinics did not provide correct information regarding treatment for E. multilocularis. Less than one in 10 clinics provided the correct information regarding both pathogens directly at the time of calling. The correct information was obtained, once taking into account secondary sources, just 62% of the time. Countrywise, most clinics in Finland provided correct advice, either directly or indirectly via referring the caller to another source, whilst the majority in Belgium, Germany and France did not. The apparent paucity of readily accessible, correct advice for owners intending to travel with their dogs is concerning. The compulsory treatment regulations are only as good as the checks that ensure compliance, and this is also lacking in some countries. © 2012 Blackwell Verlag GmbH.


Robertson L.J.,Parasitology Laboratory | Chalmers R.M.,Singleton Hospital
Trends in Parasitology | Year: 2013

Most waterborne outbreaks of cryptosporidiosis are reported from the USA, and in Europe from the UK. However, since 2000 reports of foodborne cryptosporidiosis seem to be skewed towards Nordic countries, although consumers in these countries are apparently less concerned about microbiological contamination of food than consumers elsewhere. Possible reasons for this unexpected geographical distribution might include prolonged survival of oocysts in the Nordic climate, greater exposure due to elevated consumption of higher-risk products (possibly including imported foods), and better outbreak investigation and reporting. Although the risk of foodborne cryptosporidiosis is probably underestimated globally, we suggest that the next outbreak is no more likely to be in a Nordic country than anywhere else. © 2012 Elsevier Ltd.


Rojas L.,Institute Medicina Tropical Pedro Kouri | Vazquez A.,Institute Medicina Tropical Pedro Kouri | Domenech I.,Institute Medicina Tropical Pedro Kouri | Robertson L.J.,Parasitology Laboratory
Trends in Parasitology | Year: 2010

Fascioliasis, an emerging parasitic infection, impacts significantly on both veterinary and human health worldwide. Endemic foci are not limited only to areas of extensive livestock farming, but owing to the parasite's abilities to colonise new intermediate hosts and adapt to new environments, also occur in other places, including Cuba. In Cuba, despite a high prevalence of fascioliasis in livestock, and the widespread occurrence of two potential intermediate hosts, human infection has decreased steadily over the past 10 years. In other parts of the world, human fascioliasis is apparently becoming more frequent. Problems in counteracting the spread of fascioliasis, and approaches used in Cuba to limit zoonotic transmission are discussed, with emphasis on diagnostic and treatment problems, malacological initiatives, and the importance of an integrated control programme. Such programmes may be of benefit in other countries where the prevalence of human fascioliasis is increasing, and lessons may perhaps be learned from the Cuban approach. © 2009 Elsevier Ltd. All rights reserved.

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