http://www.parasitesandvectors.com The latest research articles published by Parasites & Vectors 2012-05-10T00:00:00Z Background: Mosquito-borne viruses are transmitted to human hosts via blood-feeding behavior of female mosquitoes. Female mosquitoes seek a host to take blood meals (host-seeking behavior). In order to prevent virus infections, it is important to understand how they modulate host-seeking behavior. Dopamine (DA) in the central nervous system acts as a neuromediator that regulates a variety of behaviors in insects. In female mosquitoes, host-seeking behavior increases when DA levels in the head decline after emergence. However, it remains unclear whether DA directly modulates host-seeking behavior in female mosquitoes. The aim of this study was to examine whether changes in DA levels in the head affects host-seeking activity in the adult female mosquito Aedes albopictus (Ae. albopictus).FindingsWe compared host-seeking behavior in one group of emerging female adults treated with L-beta-3,4-dihydroxyphenylalanine (L-DOPA), the precursor of DA, (L-DOPA group), with that in an untreated control (control group) after confirming elevation of head DA in L-DOPA group by using high-performance liquid chromatography. The content of head DA in L-DOPA group significantly remained higher than that in controls on all days examined. The host-seeking activity in the control group showed a gradual increase over the 6-day experimental period. In contrast, there was no such increase in the host-seeking activity in the L-DOPA group. Therefore, the host-seeking activity of L-DOPA group was significantly lower than that of the controls between day 3 and 6 post-emergence. Conclusion: Our results indicate that elevation of DA level reduces host-seeking activity in adult female mosquito Ae. albopictus. http://www.parasitesandvectors.com/content/5/1/92 Yuki Fukumitsu Keiichi Irie Tomomitsu Satho Hitoshi Aonuma Hamady Dieng Abu Ahmad Yukihiko Nakashima Kenichi Mishima Nobuhiro Kashige Fumio Miake Parasites & Vectors 2012, null:92 2012-05-10T00:00:00Z doi:10.1186/1756-3305-5-92 Female mosquitoes show host-seeking behavior to take blood meals. Our study provides evidence that dopamine is involved in modulating host-seeking behavior in adult female Aedes albopictus. Image: Adult female Aedes albopictus. /content/figures/1756-3305-5-92-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 92 2012-05-10T00:00:00Z PDF Ascarids and ancylostomatids are the most important parasites affecting companion dogs and cats worldwide, in terms of diffusion and risk for animal and human health. Different misconceptions have led the general public and pet owners to minimize the importance of these intestinal worms. A low grade of interest is also registered among veterinary professions, although there is a significant merit in keeping our guard up against these parasites. This article reviews current knowledge of ascarids and ancylostomatids, with a special focus on pathogenicity, epidemiology and control methods in veterinary and human medicine. http://www.parasitesandvectors.com/content/5/1/91 Donato Traversa Parasites & Vectors 2012, null:91 2012-05-10T00:00:00Z doi:10.1186/1756-3305-5-91 Intestinal nematodes may parasitize from the cosseted pet to the stray animal, causing concern in veterinary and human medicine. This review focuses on pathogenicity, epidemiology and control methods of ascarids and ancylostomatids. Image: Companion dog and cats sharing the same apartment. /content/figures/1756-3305-5-91-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 91 2012-05-10T00:00:00Z PDF Background: For parasites with complex life cycles, size at transmission can impact performance in thenext host, thereby coupling parasite phenotypes in the two consecutive hosts. However, ahandful of studies with parasites, and numerous studies with free-living, complex-life-cycleanimals, have found that larval size correlates poorly with fitness under particular conditions,implying that other traits, such as physiological or ontogenetic variation, may predict fitnessmore reliably. Using the tapeworm Schistocephalus solidus, we evaluated how parasite size,age, and ontogeny in the copepod first host interact to determine performance in thestickleback second host. Methods: We raised infected copepods under two feeding treatments (to manipulate parasite growth),and then exposed fish to worms of two different ages (to manipulate parasite ontogeny). Weassessed how growth and ontogeny in copepods affected three measures of fitness in fish:infection probability, growth rate, and energy storage. Results: Our main, novel finding is that the increase in fitness (infection probability and growth infish) with larval size and age observed in previous studies on S. solidus seems to be largelymediated by ontogenetic variation. Worms that developed rapidly (had a cercomer after9 days in copepods) were able to infect fish at an earlier age, and they grew to larger sizeswith larger energy reserves in fish. Infection probability in fish increased with larval sizechiefly in young worms, when size and ontogeny are positively correlated, but not in olderworms that had essentially completed their larval development in copepods. Conclusions: Transmission to sticklebacks as a small, not-yet-fully developed larva has clear costs for S.solidus, but it remains unclear what prevents the evolution of faster growth and developmentin this species. http://www.parasitesandvectors.com/content/5/1/90 Daniel Benesh Nina Hafer Parasites & Vectors 2012, null:90 2012-05-07T00:00:00Z doi:10.1186/1756-3305-5-90 This study evaluated how larval size, age, and ontogeny of the tapeworm Schistocephalus solidus in the copepod first host interact to determine performance in the stickleback second host. Phenotypic variation in the copepod host had carryover effects in the fish host, indicating that transmission up the food web into bigger, "better" hosts does not imply a new start for parasites. Image: Copepod infected with S. solidus. /content/figures/1756-3305-5-90-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 90 2012-05-07T00:00:00Z PDF Background: Recent data from Ghana indicates that after seven rounds of annual mass drug administration(MDA) there is still sustained transmission albeit at low levels in certain areas whereAnopheles melas, An. gambiae s.s., Mansonia and Culex species are the main bitingmosquitoes. Anopheles gambiae s.l. and An. funestus are the known vectors in Ghana and arecent report indicated that An. melas could transmit at low level microfilaraemia. However,because An. melas is not found everywhere there was the need to determine whether any ofthe other culicine species could also be playing a role in the transmission of LF. Methods: Indoor mosquitoes collected once a month for three months using pyrethrum spray catches insix communities within the Kommenda-Edina-Eguafo-Abirem (KEEA) District, CentralRegion of Ghana were morphologically identified, dissected and examined for the presenceof W. bancrofti. Additionally, stored mosquito samples collected during previous years in 8communities from the Gomoa District also in the Central Region were similarly processed.The identities of all W. bancrofti parasites found were confirmed using an established PCRMethodResultsA total of 825 indoor resting mosquitoes comprising of 501 Anopheles species, 239 Mansoniaspecies, 84 Culex species and 1 Aedes species were dissected and examined for the presenceof W. bancrofti. Mansonia africana had infection and infectivity rates of 2.5%. and 2.1%respectively. Anopheles gambiae s.l. had an infection rate of 0.4% and a similar infectivityrate. None of the Culex sp. and Aedes sp were found with infection. From the storedmosquitoes the infection and infectivity rates for M. africana were 7.6% (N = 144) and 2.8%respectively whilst the corresponding rates for M. uniformis were 2.9% (N = 244) and 0.8%. Conclusions: This is the first report of Mansonia species as vectors of lymphatic filariasis (LF) in Ghanaand in West Africa since that of 1958 in Guinea. The revelation of a hitherto unrecognisedvector which is possibly more efficient in transmission than the recognised ones has aprofound implication for elimination of lymphatic filariasis programmes in the sub-region. http://www.parasitesandvectors.com/content/5/1/89 Josephine Ughasi Hilaria Bekhard Maimouna Coulibaly Delphina Adabie-Gomez John Gyapong Maxwell Appawu Michael Wilson Daniel Boakye Parasites & Vectors 2012, null:89 2012-05-07T00:00:00Z doi:10.1186/1756-3305-5-89 Anopheles species are considered the only vectors of LF in West Africa. We report Mansonia africana and Mansonia uniformis as vectors in parts of Ghana. This has important implications for LF elimination. Image: Proportion of Mansonia species in total mosquitoes collected in the Gomoa District. /content/figures/1756-3305-5-89-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 89 2012-05-07T00:00:00Z PDF Background: Canine hookworm infection is endemic in Southeast Asian countries with a prevalence ranging from 70% to 100%, with zoonotic transmission representing a potentially significant public health concern. However, there are limited data available on the prevalence of canine hookworms in Malaysia. This study was conducted to determine the prevalence of hookworm and Ancylostoma species among dogs in Malaysia. Methods: Faecal samples were collected from 221 dogs living in urban areas, rural areas and animal shelters in Selangor. Faecal samples were processed using the formal-ether concentration technique followed by wet mount preparation and iodine staining for the detection of hookworm eggs. Samples positive for hookworm eggs were examined using PCR, targeting ITS2 and 28 s rRNA region, and subsequently sequenced in both directions. The sequences were phylogenetically analysed using MrBayes for Bayesian Inference. Results: The overall prevalence of hookworm among dogs was 48% (95%CI; 41.41-54.95). Rural stray dogs had the highest prevalence 71.4% (95%CI; 61.13-81.49) followed by urban stray dogs, recording 48% (95%CI; 34.15-61.85) and lastly dogs in shelters with 28.7% (95%CI; 19.56-37.84). Logistic regression identified rural stray dogs as a high risk group (OR = 4.55, 95%; 2.50-8.31) and keeping dogs in shelters as a protective factor (OR = 0.24, 95%; 0.14-0.43). Molecular methods identified both Ancylostoma ceylanicum and Ancylostoma caninum with A. ceylanicum being predominant among urban stray dogs. Rural dogs had a higher prevalence of A. caninum than A. ceylanicum, while both species showed equal distribution among dogs in shelters. Phylogenetic analysis placed A. ceylanicum isolated from dogs in one group with A. ceylanicum human isolates. Conclusion: This study indicates that dogs have the potential to act as reservoir hosts of human hookworm infection in Malaysia. This finding necessitates the inclusion of dogs in any interventions to combat hookworm in the country. http://www.parasitesandvectors.com/content/5/1/88 Mohammed Mahdy Yvonne Lim Romano Ngui MR Siti Fatimah Seow Choy Nan Yap Hesham Al-Mekhlafi Jamaiah Ibrahim Johari Surin Parasites & Vectors 2012, null:88 2012-05-07T00:00:00Z doi:10.1186/1756-3305-5-88 This study isolated both Ancylostoma ceylanicum and Ancylostoma caninum from dogs with A. ceylanicum being predominant. This implicates dogs as potential reservoir hosts of hookworm in Malaysia. Image: Dogs in close contact with humans. /content/figures/1756-3305-5-88-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 88 2012-05-07T00:00:00Z PDF Background: The leishmaniases are a group of clinically diverse diseases caused by parasites of the genus Leishmania. To distinguish between species is crucial for correct diagnosis and prognosis as well as for treatment decisions. Recently, sequencing of the HSP70 coding region has been applied in phylogenetic studies and for identifying of Leishmania species with excellent results. Methods: In the present study, we analyzed the 3'-untranslated region (UTR) of Leishmania HSP70-type I gene from 24 strains representing eleven Leishmania species in the belief that this non-coding region would have a better discriminatory capacity for species typing than coding regions. Results: It was observed that there was a remarkable degree of sequence conservation in this region, even between species of the subgenus Leishmania and Viannia. In addition, the presence of many microsatellites was a common feature of the 3'-UTR of HSP70-I genes in the Leishmania genus. Finally, we constructed dendrograms based on global sequence alignments of the analyzed Leishmania species and strains, the results indicated that this particular region of HSP70 genes might be useful for species (or species complex) typing, improving for particular species the discrimination capacity of phylogenetic trees based on HSP70 coding sequences. Given the large size variation of the analyzed region between the Leishmania and Viannia subgenera, direct visualization of the PCR amplification product would allow discrimination between subgenera, and a HaeIII-PCR-RFLP analysis might be used for differentiating some species within each subgenera. Conclusions: Sequence and phylogenetic analyses indicated that this region, which is readily amplified using a single pair of primers from both Old and New World Leishmania species, might be useful as a molecular marker for species discrimination. http://www.parasitesandvectors.com/content/5/1/87 Jose Requena Carmen Chicharro Lineth García Rudy Parrado Concepción Puerta Carmen Cañavate Parasites & Vectors 2012, null:87 2012-04-28T00:00:00Z doi:10.1186/1756-3305-5-87 To distinguish among the twenty Leishmania species causing leishmaniasis is crucial for correct prognosis as well as for treatment decisions. We show that the 3'-UTR of HSP70-I genes may be a useful molecular marker for species typing within the Leishmania genus. Image: Giemsa-stained Leishmania infantum promastigotes, and a map of the HSP70 region analyzed in this study. /content/figures/1756-3305-5-87-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 87 2012-04-28T00:00:00Z PDF Background: Understanding the impact of reducing Plasmodium falciparum malaria transmission requires estimates of the relationship between health outcomes and exposure to infectious mosquitoes. However, measures of exposure such as mosquito density and entomological inoculation rate (EIR) are generally aggregated over large areas and time periods, biasing the outcome-exposure relationship. There are few studies examining the extent and drivers of local variation in malaria exposure in endemic areas. Methods: We describe the spatio-temporal dynamics of malaria transmission intensity measured by mosquito density and EIR in the KEMRI/CDC health and demographic surveillance system using entomological data collected during 2002-2004. Geostatistical zero inflated binomial and negative binomial models were applied to obtain location specific (house) estimates of sporozoite rates and mosquito densities respectively. Model-based predictions were multiplied to estimate the spatial pattern of annual entomological inoculation rate, a measure of the number of infective bites a person receive per unit of time. The models included environmental and climatic predictors extracted from satellite data, harmonic seasonal trends and parameters describing space-time correlation. Results: Anopheles gambiae s.l was the main vector species accounting for 86% (n=2309) of the total collected mosquitoes with the remainder being Anopheles funestus. Sixty eight percent (757/1110) of the surveyed houses had no mosquitoes. Distance to water bodies, vegetation and day temperature were significantly associated with mosquito density. Overall annual point estimates of EIR were 6.7, 9.3 and 9.6 infectious bites per annum for 2002, 2003 and 2004 respectively. Monthly mosquito density and EIR varied over the study period peaking in May during the wet season. The predicted and observed densities and EIR showed a strong seasonal and spatial pattern over the study area. Conclusions: Spatio-temporal maps of malaria transmission intensity obtained in this study are not only useful in understanding variability in malaria epidemiology over small areas but also provides a high resolution exposure surface that can be used to analyse the impact of malaria exposure on mortality. http://www.parasitesandvectors.com/content/5/1/86 Nyaguara Amek Nabie Bayoh Mary Hamel Kim Lindblade John Gimnig Frank Odhiambo Kayla Laserson Laurence Slutsker Thomas Smith Penelope Vounatsou Parasites & Vectors 2012, null:86 2012-04-28T00:00:00Z doi:10.1186/1756-3305-5-86 This study describes the spatio-temporal dynamics of malaria transmission in rural western Kenya. Bayesian zero-inflated models were used to analyze sparse geostatistical entomological data and produce smooth maps of entomological inoculation rate (EIR). Image: Spatial variation of malaria transmission measured by EIR. /content/figures/1756-3305-5-86-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 86 2012-04-28T00:00:00Z PDF Background: Among ocular vector-borne pathogens, Onchocerca volvulus, also known as the agent of the so-called "river blindness", affects about 37 million people globally. Other Onchocerca spp. have been sporadically reported as zoonotic agents. Cases of canine onchocerciasis caused by Onchocerca lupi are on the rise in the United States and Europe. Its zoonotic role has been suspected but only recently ascertained in a single case from Turkey. The present study provides further evidence on the occurrence of O. lupi infesting human eyes in two patients from Turkey (case 1) and Tunisia (case 2). The importance of obtaining a correct sample collection and preparation of nematodes infesting human eyes is highlighted. Methods: In both cases the parasites were identified with morpho-anatomical characters at the gross examination, histological analysis and anatomical description and also molecularly in case 1. Results: The nematode from the first case was obviously O. lupi based on their morphology at the gross examination, histological analysis and anatomical description. In the second case, although the diagnostic cuticular characters were not completely developed, other features were congruent with the identification of O. lupi. Furthermore, the morphological identification was also molecularly confirmed in the Turkish case. Conclusions: The results of this study suggest that O. lupi infestation is not an occasional finding but it should be considered in the differential diagnosis of other zoonotic helminths causing eye infestation in humans (e.g., D. immitis and Dirofilaria repens). Both cases came from areas where no cases of canine onchocerciasis were previously reported in the literature, suggesting that an in depth appraisal of the infestation in canine populations is necessary. Physicians and ophthalmologists are advised on how to preserve nematode samples recovered surgically, to allow a definitive, correct etiological diagnosis. http://www.parasitesandvectors.com/content/5/1/84 Domenico Otranto Filipe Dantas-Torres Zafer Cebeci Baris Yeniad Nesimi Buyukbabani Ozden Boral Andrea Gustinelli Trimèche Mounir Yasen Mutafchiev Odile Bain Parasites & Vectors 2012, null:84 2012-04-27T00:00:00Z doi:10.1186/1756-3305-5-84 Two zoonotic cases of human ocular filariosis by Onchocerca lupi are here described in patients from Turkey and Tunisia. This manuscript provides definitive evidence of human zoonotic infestation by this nematode. Image: Extraction of O. lupi from the sub-conjunctiva. /content/figures/1756-3305-5-84-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 84 2012-04-27T00:00:00Z PDF Background: Culex pipiens L. is the most widespread mosquito vector in temperate regions including North Africa. Cx. pipiens has two recognized forms or biotypes; pipiens and molestus are morphologically indistinguishable with distinct behavior and physiology that may influence their vectorial status. In our study, we prospected for the different forms of Cx. pipiens in Morocco. Methods: Cx. pipiens larvae were collected in 9 sites throughout Morocco during summer 2010 and reared until imago stage. Cx. pipiens was identified using diagnostic primers designed for the flanking region of microsatellite CQ11. Results: We established the presence of both forms of Cx. pipiens and their hybrids in Morocco. Conclusions: Molecular identification provides the first evidence of the presence of Cx. pipiens form molestus in Morocco and hybrids between pipiens and molestus forms in North Africa. The epidemiological implications of our findings are discussed. http://www.parasitesandvectors.com/content/5/1/83 Fadila Amraoui Mhamed Tijane Mhammed Sarih Anna-Bella Failloux Parasites & Vectors 2012, null:83 2012-04-27T00:00:00Z doi:10.1186/1756-3305-5-83 Our study shows that Cx. pipiens form molestus is present in Morocco and hybrids between pipiens and molestus form in North Africa. These findings have important epidemiological implications as hybrids with their opportunistic biting behavior may act as a bridge-vector for transmission of pathogens from birds to humans. Image: Larval breeding site of Culex pipiens in Morocco. /content/figures/1756-3305-5-83-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 83 2012-04-27T00:00:00Z PDF Background: The objectives of the studies listed here were to ascertain the therapeutic and sustained efficacy of 10% imidacloprid (w/w) and 4.5% flumethrin (w/w) incorporated in a slow-release matrix collar, against laboratory-infestations of fleas and ticks on cats. Efficacy was evaluated against the flea Ctenocephalides felis felis, and the ticks Ixodes ricinus, Amblyomma americanum and Rhipicephalus turanicus. The number of studies was so large that only a general overview can be presented in this abstract. Methods: Preventive efficacy was evaluated by infesting groups of cats (n = 8-10) with C. felis felis and/or I. ricinus, A. americanum or R. turanicus at monthly intervals at least, for a period of up to 8 months. Efficacy against fleas was evaluated 24 to 48 h after treatment and 24 h after infestation, and against ticks at 6 h (repellent) or 48 h (acaricidal) after infestation. Efficacy against flea larvae was evaluated over a period of 8 months by incubating viable flea eggs on blanket samples after cat contact. In all cases efficacy was calculated by comparison with untreated negative control groups. Results: Efficacy against fleas (24 h) generally exceeded 95% until study termination. In vitro efficacy against flea larvae exceeded 92% until Day 90 and then declined to 67% at the conclusion of the study on Day 230.Sustained acaricidal (48 h) efficacy over a period of eight months was consistently 100% against I. ricinus from Day 2 after treatment, 100% against A. americanum, except for 98.5% and 97.7% at two time-points, and between 94% and 100% against R. turanicus.From Day 2 until 8 months after treatment the repellent (6 h), efficacy was consistently 100% against I. ricinus, and between 54.8% and 85.4% against R. turanicus. Conclusion: The rapid insecticidal and acaricidal properties of the medicated collars against newly- acquired infestations of fleas and ticks and their sustained high levels of preventive efficacy have been clearly demonstrated. Taking into account the seasonality of fleas and ticks, the collars have the potential to prevent the transmission of vector-borne diseases and other conditions directly associated with infestation throughout the season of parasite abundance. http://www.parasitesandvectors.com/content/5/1/82 Dorothee Stanneck Eva Kruedewagen Josephus Fourie Ivan Horak Wendell Davis Klemens Krieger Parasites & Vectors 2012, null:82 2012-04-27T00:00:00Z doi:10.1186/1756-3305-5-82 Investigations on a new antiparasitic collar revealed a fast onset of and a sustainable 8 months lasting efficacy against fleas and ticks on cats. Image: Cat wearing a new antiparasitic collar, containing imidacloprid and flumethrin. /content/figures/1756-3305-5-82-toc.gif Parasites & Vectors 1756-3305 ${item.volume} 82 2012-04-27T00:00:00Z PDF