Schistosomiasis Mansoni In Urban Northeast Brazil: Influence Of Rainfall Regime On The Population Dynamics Of Biomphalaria Sp

Introduction: Our objective was to evaluate the infl uence of rainfall regime on the population dynamics of Biomphalaria in a potential urban focus of schistosomiasis in Aracaju, Brazil, during 2009-2010. Methods: Snails were collected monthly and were counted, measured and identifi ed; the level of infection and fecal contamination at the sampling sites was determined; rainfall data were obtained. Results: High levels of fecal contamination were observed, and the abundance of Biomphalaria glabrata increased during the rainy and post-rainy seasons. The snails' size was variable, and infected snails were identifi ed independently of rainfall. Conclusions: These results provide evidence of anthropogenic and climate interference in an urban focus of schistosomiasis in the Aracaju metropolitan area.465654657Pordeus, L.C., Aguiar, L.R., Quinino, L.R.M., Barbosa, C.S.A., Ocorrência das formas aguda e crônica da esquistossomose mansônica no Brasil no período de 1997 a 2006: Uma revisão de literatura (2008) Epidemiol Serv Saude, 17, pp. 163-175Souza, M.A.A., Barbosa, V.S., Wanderlei, T.N.G., Barbosa, C.S., Criadouros de Biomphalaria, temporários e permanentes, em Jaboatão dos Guararapes, PE (2008) Rev Soc Bras Med Trop, 41, pp. 252-256Araújo, K.C.G.M., Resendes, A.P.C., Souza-Santos, R., Silveira Jr., J.C., Barbosa, C.S., Análise espacial dos focos de Biomphalaria glabrata (Say, 1818) e de casos humanos de esquistossomose mansônica em Porto de Galinhas, Pernambuco, Brasil, no ano 2000 (2007) Cad Saude Publica, 23, pp. 409-417Lima, L.C., Família Planorbidae (1995) Tópicos em Malacologia Médica., pp. 90-112. , In: Barbosa FS, editor. Rio de Janeiro: Fundação Oswaldo Cruz(2005) Resolução CONAMA no 357, , http://www.cetesb.sp.gov.br/Agua/praias/res_conama_357_05.pdf, Conselho Nacional do Meio Ambiente (CONAMA). de 17 de março de. [Cited 2011 February 23]. Available fromSouza, M.A.A., Barbosa, V.S., Albuquerque, J.O., Bocanegra, S., Souza-Santos, R., Paredes, H., Aspectos ecológicos e levantamento malacológico para identificação de áreas de risco para transmissão da esquistossomose mansoni no litoral norte de Pernambuco, Brasil (2010) Iheringia Serie Zoológica, 100, pp. 19-24Barbosa, F.S., Barbosa, C.S., The bioecology of snails vectors for schistosomiasis in Brazil (1994) Cad Saude Publica, 10, pp. 200-209Fernandez, M.A., Thiengo, S.C., Susceptibility of Biomphalaria straminea from Peixe Angical dam, Tocantins, Brazil to infection with three strains of Schistosoma mansoni (2010) Mem Inst Oswaldo Cruz, 105, pp. 488-491Barbosa, C.S., Domingues, A.L.C., Abath, F., Montenegro, S.M.L., Guida, U., Carneiro, J., Epidemia de esquistossomose aguda na praia de Porto de Galinhas, Pernambuco, Brasil (2001) Cad Saude Publica, 17, pp. 725-728Rollemberg, C.V.V., Santos, C.M.B., Silva, M.M.B.L., Souza, A.M.B., Silva, A.M., Almeida, J.A.P., Aspectos epidemiológicos e distribuição geográfica da esquistossomose e geo-helmintos, no Estado de Sergipe, de acordo com os dados do Programa de Controle da Esquistossomose (2011) Rev Soc Bras Med Trop, 44, pp. 91-96Barbosa, C.S., Montenegro, S.M.L., Abath, F.G., Domingues, A.L.C., Eventos epidemiológicos relacionados à transmissão da esquistossomose em áreas rurais e urbanas de Pernambuco (2002) Mem Inst Oswaldo Cruz, 96, pp. 169-172Departamento de Vigilância Epidemiológica (2008) Vigilância e controle de moluscos de importância epidemiológica: Diretrizes técnicas., , Ministério da Saúde. Programa de Vigilância e Controle da Esquistossomose (PCE). 2nded. Brasília: Ministério da Saúd

The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

The Role Of Ancyrocephalinae (monogenea: Dactylogyridae), Parasite Of Geophagus Brasiliensis (pisces: Cichlidae), As An Environmental Indicator [o Papel De Ancyrocephalinae (monogenea: Dactylogyridae), Parasito De Geophagus Brasiliensis (pisces: Cichlidae), Como Indicador Ambiental]

The variations in the parasite population of fishes may be indicative of environmental alterations. With the aim of studying the variation of the parasitism by Ancyrocephalinae in Geophagus brasiliensis, two reservoirs of distinct trophic caracterizations (Juqueri - eutrophic and Jaguari - oligomesotrophic) were compared. The prevalence rates and intensity of infection of this parasite were measured bimonthly for one year. The results showed that the prevalence and the intensity of infection vary in according to the alteration in the storage level of the reservoirs and consequently to the variations in the amount of material in suspension in the water.1823841Ayres, M., (2000) BioEstat 2.0: Aplicações estatísticas nas áreas de ciências biológicas e médicas, p. 272. , Belém: Sociedade Civil Mamirauá/MCT-CNPQBakke, T.A., Harris, P.D., Cable, J., Host specifcity dynamics: Observations on gyrodactylid monogeneans (2002) International Journal for Parasitology, 32 (3), pp. 281-308Bush, A.O., Parasitology meet ecology on its own Therms: Margolis et al. revisited (1997) Journal of Parasitology, 83 (4), pp. 575-583Chubb, J.C., Seasonal ocurrence of helminths in freshwater fishes. Part I. Monogenea (1977) Advances in Parasitology, 15, pp. 133-199Chubb, J.C., Seasonal ocurrence of helminths in freshwater fishes. Part III. Larval Cestoda and Nematoda (1980) Advances in Parasitology, 18, pp. 1-120Chubb, J.C., Seasonal ocurrence of helminths in freshwater fishes. Part IV. Adult Cestoda, Nematoda and Acanthocephala (1982) Advances in Parasitology, 20, pp. 1-292Situação dos Mananciais, , http://www.sabesp.com.br, COMPANHIA DE SANEAMENTO BÁSICO DO ESTADO DE SÃO PAULO - SABESP, Disponível em, Acesso em: Agosto de 2001 e Novembro de 2002Eiras, J.C., (1994) Elementos de Ictioparasitologia, p. 339. , Porto: Fundação Eng. António AlmeidaEiras, J.C., Takemoto, R.M., Pavanelli, G.C., (2000) Métodos de estudo e Thécnicas laboratoriais em parasitologia de peixes, p. 173. , Maringá: Editora Universidade Estadual de MaringáEuzet, L., Combes, C., The selection of habitats among the monogenea (1998) International Journal for Parasitology, 28 (10), pp. 1645-1652Khan, R.A., Kiceniuk, J.W., Effect of petroleum aromatic hydrocarbons on monogenoids parasitizing Atlantic cod, Gadus morhua L (1988) Bulletin of Environmental Contamination and Toxicology, 41 (1), pp. 94-100Kritsky, D.C., Boerger, W.A., Popazoglo, F., Neotropical Monogenoidea. 22. Variation in Scleroductus species (Gyrodactylidea, Gyrodactylidae) from Siluriform fishes of southeastern Brazil (1995) Journal of the Helminthological Society of Washington, 62 (1), pp. 53-56Mackenzie, K., Parasites as indicators of water quality and the potential use of helminth transmission in marine pollution studies (1995) Advances in Parasitology, 35, pp. 85-144Moles, A., Wade, T., L. Parasitism and phagocytic function among sand lance Ammodytes hexapterus Pallas exposed to crude oil-laden sediments (2001) Bulletin of Environmental Contamination and Toxicology, 66 (4), pp. 528-535Overstreet, R.M., Parasitological data as monitors of environmental health (1997) Parassitologia, 39 (3), pp. 169-175Putz, R.E., Hoffman, G.L., Two new Gyrodactylus (Trematoda, Monogenea) from cyprinid fishes with synopsis of those found on North American fishes (1963) Journal of Parasitology, 49 (4), p. 559Salas, H.J., Martino, P., A simplifed phosphorus trophic state model for warm-water tropical lakes (1991) Water Research, 25 (3), pp. 341-350SAS User's Guide: Statistics (1996), p. 1098. , SAS INSTITUTE INCORPORATION, Release 6.12., North Caroline, CorySkinner, R.H., The interrelation of water quality, gill parasites, and gill pathology of some fishes from south Biscayne Bay, Florida (1982) Fishery Bulletin, 80 (2), pp. 269-280Sures, B., Environmental parasitology: Relevancy of parasites in monitoring environmental pollution (2004) Trends in Parasitology, 20 (4), pp. 170-177Valtonen, E.T., Holmes, J.C., Koskivaara, M., Eutrophication, pollution and fragmentation: Efects on the parasite communities in roach and perch in four lakes in Central Finland (1997) Parassitologia, 39 (3), pp. 233-23

Copepods Notodiaptomus Sp. Kiefer (crustacea, Calanoida) Naturally Infected By Metacestodes In The Juqueri Reservoir, São Paulo, Brazil [copépodos Notodiaptomus Sp. Kiefer (crustacea, Calanoida) Naturalmente Infectados Com Metacestódeos No Reservatório Do Juqueri, São Paulo, Brasil]

The aim of this work was to identify the components of zooplankton that act as intermediate hosts of cestodes. One hundred and ninety four copepods of the suborder Calanoida, 317 copepods of the suborder Cyclopoida and 4240 cladocerans were collected in the Juqueri reservoir, in the state of São Paulo, from January to August, 2003. Only Copepods Calanoida of the genus Notodiaptomus sp. Kiefer were found to be infected and contained two distinct forms of metacestodes. The metacestodes, denominated Met 1 (order Proteocephalidea) and Met 2 (order Cyclophyllidea), had the following rates of prevalence and mean intensities of infection: Met 1 - 2.06% and 64 larvae/copepod and Met 2 - 0.52% and one larvae/copepod. The positive copepods were collected at the margins of the reservoir during the day. This finding suggest that parasitism may lead to a change in the behavior of the copepods and make them more susceptible to predation in shallow water.112179182Bush, A.O., Lafferty, K.D., Lotz, J.M., Shostak, A.W., Parasitology meet ecology on its own terms: Margolis et al. revisited (1997) J. Parasitol., 83 (4), pp. 575-583. , http://dx.doi.org/10.2307/3284227Dupont, F., Gabrion, C., The concept of specificity in the procercoid-copepod system: Bothrocephalus claviceps (Cestoda) a parasite of the eel (Anguilla anguilla) (1987) Parasitol. Res., 73 (2), pp. 151-158. , http://dx.doi.org/10.1007/BF00536472Esch, G.W., The population and community ecology of cestodes (1983) Biology of Eucestoda, 1, pp. 81-137. , (C. Arme & P.W. Pappas eds.). Academic Press, LondresEsteves, F.A., (1998) Fundamentos De Limnologia, , 2nd ed. Interciência, Rio de JaneiroFalavigna, D.L.M., Pavanelli, G.C., Takemoto, R., Resultados preliminares do ciclo evolutivo de cestóides parasitas de Pseudoplatystoma corruscans da planície de inundação do alto do Rio Paraná, Brasil (2000) VI Encontro Brasileiro De Patologistas De Organismos Aquáticos, p. 133. , Universidade Federal de Santa Catarina e ABRAPOA, FlorianópolisFalavigna, D.L.M., Velho, L.F.M., Pavanelli, G.C., Proteocephalidean larvae (Cestoda) in naturally infected Cyclopid copepods of the upper Paraná river floodplain (2003) Brazil. Mem. Inst. Oswaldo Cruz., 98 (1), pp. 69-72. , http://dx.doi.org/10.1590/S0074-02762003000100009Franz, K., Kurtz, J., Altered host behaviour: Manipulation or energy depletion in tapeworm-infected copepods? (2002) Parasitology, 125 (2), pp. 187-196. , http://dx.doi.org/10.1017/S0031182002001932Hanzelová, V., Gerdeaux, D., Seasonal ocurrence of the tapeworm Proteocephalus longicollis and its transmission from copepod intermediate host to fish (2003) Parasitol. Res., 91 (2), pp. 130-136. , http://dx.doi.org/10.1007/s00436-003-0939-xMadi, R.R., Ueta, M.T., Estudo comparativo dos metazoários parasitas de Geophagus brasiliensis (Cichlidae, Perciforme) em dois reservatórios no estado de São Paulo (2002) VII Encontro Brasileiro De Patologistas De Organismos Aquáticos, p. 137. , UEM, Foz do IguaçuMarcogliese, D.J., The role of zooplankton in the transmission of helminth parasites to fish (1995) Rev. Fish Biol. Fisher., 5, pp. 336-371. , http://dx.doi.org/10.1007/BF00043006Marcogliese, D.J., Esch, G.W., Experimental and natural infection of planktonic anb benthic copepods by the asian tapeworm, Bothriocephalus acheilognathi (1989) Proc. Helminthol. Soc. Wash., 56 (2), pp. 151-155Olsen, O.W., Animal parasites (1974) Their Life Cicles and Ecology, , Univ. Park Press, BaltimorePasternak, A.F., Pulkkinen, K., Mikheev, V.N., Hasu, T., Valtonen, E.T., Factors affecting abundance of Triaenophorus infection in Cyclops strenuus, and parasite-induced changes in host fitness (1999) Int. J. Parasitol., 29 (11), pp. 1793-1801. , http://dx.doi.org/10.1016/S0020-7519(99)00108-3Pereira, C., Vianna, D.M., Azevedo, P., Biologia do nematóide Procamallanus cearensis n. sp (1936) Arch. Inst. Biológico., 7, pp. 209-226Pulkkinen, K., Pasternak, A.F., Hasu, T., Valtonen, E.T., Effect of Triaenophorus crassus (Cestoda) infection on behavior and susceptibility to predation of the first intermediate host Cyclops strenuus (Copepoda) (2000) J. Parasitol., 86 (4), pp. 664-670Rego, A.A., Order Protocephalidea Mola, 1928 (1994) Keys to The Cestode Parasites of Vertebrates, pp. 257-293. , (L.F. Khalil, A. Jones, & R.A. Bray eds.). CAB International, WallingfordRoberts, L.S., Janovy Jr., J., (1996) Foundations of Parasitology, , 5nd ed. WCB Publishers, DubuqueRusinek, O.T., Bakina, M.P., Nikolskii, A.V., Natural infection of the calanoid crustacean Epischura baicalensis by procercoids of Proteocephalus sp (1996) Listvenichnyi Bay, Lake Baikal. J. Helminthol., 70 (3), pp. 237-247. , http://dx.doi.org/10.1017/S0022149X00015479Schmidt, G.D., (1986) Handbook of Tapeworm Identification, , CRC Press, Boca RatonScholz, T., The life cycles of species of Proteocephalus, parasites of fishes in Palearctic Region: A review (1999) J. Helminthol., 73 (1), pp. 1-19van der Veen, I.T., Is body size or activity of copepods related to ingestion of parasite larvae? (2003) Parasitology, 126 (2), pp. 173-178. , http://dx.doi.org/10.1017/S0031182002002652van der Veen, I.T., Kurtz, J., To avoid or eliminate: Cestode infections in copepods (2002) Parasitology, 124 (4), pp. 465-474. , http://dx.doi.org/10.1017/S0031182001001275Wedekind, C., The infectivity, growth, and virulence of the cestode Schistocephalus solidus in its first intermediate host, the copepod Macrocyclops albidus (1997) Parasitology, 115 (3), pp. 317-324. , http://dx.doi.org/10.1017/S003118209700140

Effect Of Praziquantel In Liposomes On Schistosoma Mansoni Eggs At Different Development Stages [efeito Do Praziquantel Incorporado A Lipossomas Nos Diferentes Estágios De Desenvolvimento Dos Ovos De Schistosoma Mansoni]

Mansonian schistosomiasis is caused by an intravascular digenetic trematode Schistosoma mansoni. Praziquantel (PZQ) and oxamniquine (OXA) are the drugs of choice for the treatment of this disease. However, both drugs are subject to some limitations in their action and cases of tolerance and resistance have been reported. Moreover, tolerance and resistance cases have been reported. For this reason, there is an urgent need for research on new alternatives aimed at improving the action of existing drugs, such as the incorporation of these drugs into liposomes. In this study, the efficiency of action of liposome- encapsulated praziquantel (lip.PZQ) on oviposition by S. mansoni, strain BH, was assessed in Mus musculus mices (SPF Swiss mice). Four PZQ and lip.PZQ doses (47; 60; 250 e 300mg/kg) were tested. Some mice were treated 30 days post-infection and others after 45 days. The oogram analyses showed that the most effective lip.PZQ treatment was 300mg/kg dose given on the 45th day post infection, which reduced the number of S. mansoni eggs per gram of tissue.282209214Barth, L.R., Fernandes, A.P., Rodrigues, V., Oviposition by Schistosoma mansoni during in vitro cultivation (1996) Rev Inst Med Trop São Paulo, 38, pp. 423-426Blanchard, T.J., Milne, L.M., Pollock, R., Coock, G.C., Early chemotherapy of imported neuroschistosomiasis (1993) Lancet, 341 (8850), p. 959Bonesso-Sabadini PIP. Avaliação da suscetibilidade da linhagem Ouh (Ourinhos, Vale do Paranapanema - SP) de Schistosoma mansoni ao oxamniquine e praziquantel [Dissertação] Campinas: Instituto de Biologia, UNICAMP, 1995Christopherson, J.B., The successful use of antimiony in bilhaziasis (1918) Lancet, 2, pp. 325-327Cinto, P.O., Avaliação da absorção intestinal de praziquantel veiculado em lipossomas (2005) Araraquara: Faculdade de Ciências Farmacêuticas, , Dissertação, UNESPCunha, A.S., Schistosomiasis mansoni - drug therapeutic (1992) Mem Inst Oswaldo Cruz, 87 (SUPPL. 4), pp. 341-351Delgado, V.S., Suárez, D.P., Cesari, I.M., Hincan, R.N., Experimental chemotherapy of Schistosoma mansoni with praziquantel and oxamniquine: Differential effect of single or combined formulations of drugs on various strins on both sexes of the parasite (1992) Prasitol Res, 78, pp. 648-654El-Ridi, R., Ozaki, T., Inaba, T., Ito, M., Kamiya, M., Schistosoma mansoni oviposition in vitro reflects worm fecundity in vivo: Individual, parasite age and host dependent variations (1997) Int J Parasitol, 27, pp. 381-387Frézard, F., Melo, A.L., Evaluation of the schistomicidal efficacy of lipossome-entrapped oxamniquine (1997) Rev Inst Med Trop São Paulo, 39 (2), pp. 91-100Frezza TF. Avaliação do efeito do praziquantel associado a lipossomas em Schistosoma mansoni in vivo [Dissertação] Campinas: Instituto de Biologia, UNICAMP, 2007Gönnert, R., Andrews, P., Praziquantel, a new broad-spectrum antischistosomal agent (1977) Z Parasitenkd, 52, pp. 129-150Hill, J., Rust, M.A., Pellegrino, J., Faria, J., Use of the oogram to reveal the effect of a nitrofurylacrylamide on the eggs of Schistosoma mansoni (1966) J Parasitol, 52, p. 822Kikuth, E., Gönnert, R., Experimental studies on the therapy of schistosomiasis (1948) Ann Trop Med Parasitol, 42, pp. 256-267Lambert, C.R., Chemotherapy of experimental Schistosoma mansoni infection with a nitro-thiazole derivate, CIBA 32,644-Ba (1964) Ann Trop Med Parasitol, 58, pp. 293-303Martinez, E.M., Neves, R.H., Oliveira, R.M.F., Machado-Silva, J.R., Rey, L., Características biológicas e morfológicas de cepas brasileiras de Schistosma mansoni em Mus musculus. (2003) Rev Soc Bras Med Trop, 36 (5), pp. 557-564Monteiro, W., Pellegrino, J., Silva, M.L.H., Unusual oogram pattern in mice after niridazole treatment (1968) J Parasitol, 54, pp. 175-176Mourão, S.C., Preparação e caracterizaçã o de lipossomas contendo praziquantel (2001) Araraquara: Faculdade de Ciências Farmacêuticas, , Dissertação, UNESP;Mourão, S.C., Costa, P.I., Salgado, H.R.N., Gremião, M.P.D., Improvement of antischistosomal activity of praziquantel by incorporation into phosphatidylcholine-containing liposomes (2005) Int J Pharm, 295, pp. 157-162Olivier, L., Stirewalt, M.A., An efficient meted for exposure of mice to cercarie of Schistosoma mansoni (1952) J Parasitol, 38, pp. 19-23Paraense, W.L., Corrêa, L.R., Variation in susceptibility of populations of Australorbis glabratus to strain of Schistosoma mansoni (1963) Rev Inst Med Trop São Paulo, 5, pp. 15-22Pellegrino, J., Oliveira, C.A., Faria, J., Cunha, A.S., New approach to the screening of drugs in experimental schistosomiasis mansoni in mice (1962) Am J Trop Med Hyg, 11, pp. 201-215Pellegrino, J., Katz, N., Experimental chemotherapy of schistosomiasis mansoni (1968) Adv Parasitol, 6, pp. 233-290Pimentel-Gomes, F., (2000) Curso de estatística experimental, , 14.ed. Piracicaba: USP/ESALQ;, 477pPrata, A., Tipos de ovos de Schistosoma mansoni (1957) Biópsia retal na esquistossomose mansoni: Bases e aplicações no diagnóstico e tratamento, pp. 15-60. , Rio de Janeiro: Serviço Nacional de Educação Sanitária;Richards, H.C., Foster, R., A new series of 2-aminomethytetra hydroquinaline derivates displaying schistosomicidal activity in rodents and primates (1969) Nature, 222, pp. 581-582Richards, F., Sullivan, J., Ruiz-Tiben, E., Eberhard, M., Bishop, H., Effect of praziquantel on the eggs of Schistosoma mansoni, with a note on the implications for managing central nervous system schistosomiasis (1989) Ann Trop Med Parasitol, 83 (5), pp. 465-472(1996) SAS user's guide, , SAS Institute Incorporation, statistics release 6.12. North Caroline: Cory;, 1098pStirewalt, M.A., Effect of snail maintenance temperatures on development of Schistosoma mansoni (1954) Exp Parasitol, 3, pp. 504-516Thomas, H., Gönnert, R., The efficacy of praziquantel against cestodes in animals (1977) Z Parasitenkd, 52, pp. 117-127Wahl, S.M., Frazier-Jessen, M., Jin, W.W., Kopp, J.B., Sher, A., Cheever, A.W., Cytokine regulation of schistosome-induced granuloma and fibrosi (1997) Kidney Int, 5, pp. 1370-137