Prevalence and Classification of Amphistomes in Cattle and Buffaloes

Amphistomes are snail-borne trematodes infect rumens and reticulums capable of causing acute and chronic disease in cattle and buffaloes. A total of 897 of cattle and buffaloes were examined by faecal examinations and by postmortem examinations in Giza and Garbia governourates. The collected Amphistomes were morphologically and histologically classified. We found that the incidence of Amphistomes in totally examined animals was 4.9%. The incidence was higher in the oldest animals(than young), in the spring (than other seasons) and in Garbia (than Giza). But the incidence was the same in males and females. The collected Amphistomes were classified as Paramphistomum microbothrium, Paramphistomum cervi and Carmyerius gergaerius. We concluded that Amphistomes are prevalent among the examined cattle and buffaloes in Giza and Garbia governorates.

A new genus and species of amphistome parasite (Trematoda: Cladorchiidae) from a fish of Rondônia State, Brazil

A new genus and species of amphistome parasite (Trematoda: Cladorchiidae) is described from a characid fish, Curimata vittata GUNTHER, taken in the Brazilian state of Rondônia. The new amphistome is of a very small size (609-774 μm) and has a relatively large pharynx and a large acetabulum. It differs from the other small amphistomes known by possessing diagonal testes and a prominent genital sucker. Additionally, the eggs are large (100 x 60 μm) and few in number (1-4)

Epidemiological studies on bovine fasciolosis in Botswana

Fasciolosis, commonly known as liver fluke disease, is a disease of the liver of domestic livestock, principally ruminants, caused by pathogenic trematodes of the genus Fasciola, which comprises two species, F. hepatica and F. gigantica. Fasciola hepatica is the more common and important of the two, with a worldwide distribution, whereas F. gigantica is more restricted, found primarily in warmer parts of the world where it causes tropical fasciolosis in cattle, sheep and goats. Fasciola gigantica infection in cattle is potentially one of the most important parasitoses affecting the productivity of herds in many developing countries by being an impediment to reproduction and growth, causing damage to livers, which can occasionally become inedible for humans and, in some cases, can result in the death of affected animals. The economic importance of fasciolosis is mainly due to direct losses from condemnation of infected livers during meat inspection at abattoirs. The disease is also a zoonosis, however, it is rarely diagnosed in humans. Prior to the study reported in this thesis, little was known on the epidemiology of this parasitic disease in Botswana. Therefore, the main aim for undertaking this study was to determine the prevalence and estimate the economic significance of fasciolosis in cattle, as well as to determine the geographical distribution of the intermediate host snail, Lymnaea natalensis. Lymnaea natalensis is an aquatic snail that has generally been accepted as the intermediate host that plays an essential role in the epidemiology of F. gigantica infection in Africa, even though a miscellany of other Lymnaeid snails can be involved in the transmission of the fluke. The present study determined the prevalence and assessed the economic importance of F. gigantica infections in cattle through retrospective and prospective studies, by acquisition of data from meat inspection records and regular visitation to inspect livers of slaughtered cattle at selected abattoirs, respectively. In addition, a cross-sectional survey of fasciolosis was carried out through a coprological examination of live animals to determine the prevalence in live cattle from six districts in Botswana. This information will be used as the basis for future epidemiological surveillance of this important parasitic disease of ruminants in Botswana. An understanding of the epidemiology of fasciolosis and distribution of the intermediate host would assist in the design of appropriate control programmes in Botswana. The results from the present study have indicated that F. gigantica infection is present in cattle in Botswana, but the prevalence is very low (0.74%; 95% CI: 0.57, 0.94%) and not widespread as previously anticipated. The disease was present in only one (Central) of the six districts covered by this study, and was localized within the Tuli Block area, in Machaneng village, at the eastern margin of the country. Although the exact geographical origins of some of the fasciolosis-positive cattle was occasionally difficult to ascertain in abattoirs in the south of the country, it was highly likely that they originated from the northern part of the country and were already infected before being moved to the south, where they were eventually sent to the abattoirs. The prevalence reported in this study rank among the lowest, not just in Africa, but the world as a whole, in terms of prevalence, infection intensity and economic impact in cattle. The study also revealed that the only species of liver fluke found in Botswana is F. gigantica. The results of the financial losses demonstrated a low financial burden as a consequence of condemnation of Fasciola-infected livers during the twelve-year period under consideration. These findings suggest that bovine fasciolosis is neither a major cause of liver condemnations at abattoirs nor a significant cause of reduced productivity in cattle in Botswana. In spite of the low prevalence of F. gigantica infections in cattle, the disease showed a significantly higher prevalence in adult animals than weaners and calves. Gender differences in susceptibility were observed, with females demonstrating a significantly higher infection than males. Also of note was an indication of breed differences in susceptibility to infection. The Brahman and Brahman crosses exhibited a higher prevalence whereas the Nguni cattle showed no infection at all. These findings imply varying levels of immunity in these breeds, with a higher resilience and resistance shown by the Nguni native breed. The population dynamics of the intermediate host snail, L. natalensis, was not determined since no snails were detected from the potential habitats investigated. The failure to detect snails was most likely linked to the drought that prevailed in Botswana during the two years this research was carried out. The present study was able to reveal the existence of concurrent natural infection of cattle with liver fluke, F. gigantica, and the stomach fluke, amphistome, in Botswana. There was a significant positive association between the two trematode infections, as has also been reported in other parts of Africa. However, the prevalence of co-infection was low (0.16%; 95% CI: 0.09, 0.27%) and this could be attributable to the absence of F. gigantica infection in the other five districts of study. It is concluded that infection of cattle from Botswana, with F. gigantica, is low and the distribution of the fluke is linked to suitable environmental and climatic conditions for the intermediate host

First report of Paramphistomum leydeni Näsmark, 1937 (Trematoda: Paramphistomidae) in Argentina, and re-examination of Cotylophoron cotylophorum sensu Racioppi et al. (1994)

Cotylophoron cotylophorum and Balanorchis anastrophus are the only amphistomes of ruminants that have been described so far in Argentina. Recent observations suggest that C. cotylophorum could have been misclassified. To confirm this, we examined specimens, collected in Corrientes Province and classified by Racioppi et al. (1994) as Cotylophoron cotylophorum, and re-classified these as Paramphistomum leydeni Näsmark, 1937. Flukes collected from Zárate (Buenos Aires) were also studied and compared against the former, resulting in the same species. The present study reports the existence of P. leydeni in Argentina, modifies the previous classification of C. cotylophorum and suggests that, based on the evidence of the amphistomes described so far, P. leydeni would be the most prevalent species in cattle of Argentina.Facultad de Ciencias VeterinariasCentro de Estudios Parasitológicos y de Vectore

First report of Paramphistomum leydeni Näsmark, 1937 (Trematoda: Paramphistomidae) in Argentina, and re-examination of Cotylophoron cotylophorum sensu Racioppi et al. (1994)

Cotylophoron cotylophorum and Balanorchis anastrophus are the only amphistomes of ruminants that have been described so far in Argentina. Recent observations suggest that C. cotylophorum could have been misclassified. To confirm this, we examined specimens, collected in Corrientes Province and classified by Racioppi et al. (1994) as Cotylophoron cotylophorum, and re-classified these as Paramphistomum leydeni Näsmark, 1937. Flukes collected from Zárate (Buenos Aires) were also studied and compared against the former, resulting in the same species. The present study reports the existence of P. leydeni in Argentina, modifies the previous classification of C. cotylophorum and suggests that, based on the evidence of the amphistomes described so far, P. leydeni would be the most prevalent species in cattle of Argentina.Facultad de Ciencias VeterinariasCentro de Estudios Parasitológicos y de Vectore

A NEW GENUS OF DISTOMES (TREMATODA) WITH LYMPHATIC VESSELS

The trematodes described in this paper are but two of over 100 species collected from marine fishes in 1934, during the third G. Allan Hancock Expedition to the Galapagos Islands. The author\u27s presence on this expedition was sponsored in part by the Carnegie Institution of Washington. A brief preliminary report on the trematodes collected has been made (Manter, 1934) and a more complete report on the digenetic forms is in preparation. An early description of these two forms is felt justified in view of their significance in connection with the phylogeny of the Distomata. The author has already indicated (Manter, 1935) a relationship between certain allocreadiid-like distomes (Megasolena Linton and Hapladena Linton) and amphistomes. The new genus described below further substantiates such a view and indicates that the Anallocreadiinae in particular may be involved. A discussion of these relationships will follow a description of the new species

Intestinal helminths as population markers of the Amazonian fish Mylesinus paraschomburgkii, with descriptions of five new genera and seven new species of trematodes

Helminths from the intestinal tracts of fish called "pacus" were studied. The fish were found only in rapids areas of Northeastern tributaries of the Amazon River. Since this species, Mylesinus paraschomburgkii JÉGU, SANTOS & FERREIRA, 1989, does not migrate, each river has a separate population in its upper reaches. These populations are believed to have been isolated from each other, by high water, since the last glaciation some 12,000 years ago. It was thought that differences in the helminth faunas might reflect such isolation. Collection sites were: the Uatumà, Pitinga and Capucapu Rivers, Amazonas State (considered one population), the Trombetas and Jari Rivers, Pará State and the Araguari River, Amapá State. Seven species of trematodes were found, namely: Alphamphistoma canoefomta gen. et sp. nov. which has a body that is extremely concave ventrally and short ceca; Betamphistoma jariense gen. et sp. nov. which has parallel testes and a cirrus sac with heavy muscular walls, Gammamphistoma collaris gen. et sp. nov. a small species with large suckers and an anterior collar; Deltamphistoma pitingaense gen. et sp. nov. a form with short to moderately long ceca and testes that extend laterally beyond them; Zetamphistoma compacta gen. et sp. nov. with a wide body that is convex on both surfaces and thin marginally; Pseudocladorchis cyclindricus (DIESING, 1836) with a large cylindrical body. parallel testes and vitelline follicles that extend anteriorly to beyond them and the Haploporidae, Saccocoelioides rotundus sp. nov. which has a compact body, rounded posteriorly and vitellaria that nearly surround the testis. P. cylindricus was found at all sites except the Jari River. The latter has also been repotted from other hosts. From three to four species of trematodes were found in each host population and some of these appear to be useful as markers. D. pitingaense was found only in the Amazonas State population and B. jariense appeared only in fish from the Jari River. The haploporid, S. rotundus was found in the Trombetas River population exclusively. The most typical trematode from Araguari River hosts was Z. compacta but this species was also found in fìsh from the Trombetas River. Two nematode species representing the family Atractidae, namely: Proatractis sp. and Rondonia rondoni TRAVASSOS, 1919, were found in all the fish examined. The former inhabits the pyloric ceca and the fìrst three or four centimeters of upper intestinal tract whereas R. rondoni completely packs the rest of the gut. Another nematode, Cucullanus sp. (Cucullanidae), was found in numbers from 1-24 in the upper intestinal tracts of hosts from the Trombetas River only