Descriptive studies of the Genus paramphistomum Fischoeder, 1901 in some Nigerian cattle

No Abstract. Discovery and Innovation Vol. 17(3&4) 2005: 186-19

Plasmodium/intestinal helminth co-infections among pregnant Nigerian women

Hospital based studies were conducted to investigate the occurrence of Plasmodium/intestinal helminth co-infections among pregnant Nigerian women, and their effects on birthweights, anaemia and spleen size. From 2,104 near-term pregnant women examined, 816 (38.8%) were found to be infected with malaria parasites. Among the 816 parasitaemic subjects, 394 (48.3%) were also infected with intestinal helminths, 102 (12.5%) having mixed helminth infections. The prevalence of the helminth species found in stool samples of parasitaemic subjects examined was, Ascaris lumbricoides (19.1%), hookworm (14.2%), Trichuris trichiura (7%) Schistosoma mansoni (3.4%), Enterobius vermicularis (2%), Hymenolepis sp. (1.6%) and Taenia sp. (1%). Mothers with Plasmodium infection but without intestinal helminth infection had neonates of higher mean birthweights than those presenting both Plasmodium and intestinal helminth infections and this effect was more pronounced in primigravids. The mean haemoglobin values of malarial mothers with intestinal helminth infections were lower than those with Plasmodium infection but without intestinal helminth infections but these were not statistically significant. Severe splenomegaly was predominant among parasitaemic gravidae who also harboured S. mansoni infection in two of the hospitals studied

Bloodmeal microfilariae density and the uptake and establishment of Wuchereria bancrofti infections in Culex quinquefasciatus and Aedes aegypti

The relationship between ingestion of microfilariae (mf), production of infective larvae (L3) and mf density in human blood has been suggested as an important determinant in the transmission dynamics of lymphatic filariasis. Here we assess the role of these factors in determining the competence of a natural vector Culex quinquefasciatus and a non vector Aedes aegypti to transmit Wuchereria bancrofti. Mosquitoes were infected via a membrane feeding procedure. Both mosquito species ingested more than the expected number of microfilariae (concentrating factor was 1.28 and 1.81 for Cx. quinquefasciatus and Ae. aegypti, respectively) but Cx. quinquefasciatus ingested around twice as many mf as Ae. aegypti because its larger blood meal size. Ae. aegypti showed a faster mf migration capacity compared to Cx. quinquefasciatus but did not allow parasite maturation under our experimental conditions. Similar proportions of melanized parasites were observed in Ae. aegypti (2.4%) and Cx. quinquefasciatus (2.1%). However, no relationship between rate of infection and melanization was observed. We conclude that in these conditions physiological factors governing parasite development in the thorax may be more important in limiting vectorial competence than the density of mf ingested

Mermithid nematodes found in adult <it>Anopheles</it> from southeastern Senegal

<p>Abstract</p> <p>Background</p> <p>Over two dozen mermithid nematodes have been described parasitizing mosquitoes worldwide, however, only two species were found in Africa. Mermithid nematodes kill their mosquito host upon emergence, which suggests that they could be developed as biological control agents of mosquitoes. Both <it>Romanomermis culicivorax</it> and <it>Romanomermis iyengari</it> have been reared for mass release to control numerous <it>Anopheles</it> species vector populations, and in one instance this may have led to reduced malaria prevalence in a human population.</p> <p>Methods</p> <p><it>Anopheles</it> mosquitoes were collected during a malaria study in southeastern Senegal. Two different adult blood fed mosquitoes had a single mermithid nematode emerge from their anus while they were being held post-capture. Primers from the 18 S rDNA were developed to sequence nematode DNA and screen mosquitoes for mermithid DNA. 18 S rDNA from the Senegalese mermithid and other mermithid entries in GenBank were used to create a Maximum Parsimony tree of the Mermithidae family.</p> <p>Results</p> <p>The mermithid was present in 1.8% (10/551) of the sampled adult <it>Anopheles</it> species in our study area. The mermithid was found in <it>An. gambiae</it> s.s., <it>An. funestus</it>, and <it>An. rufipes</it> from the villages of Ndebou, Boundoucondi, and Damboucoye. Maximum parsimony analysis confirmed that the nematode parasites found in <it>Anopheles</it> were indeed mermithid parasites, and of the mermithid sequences available in GenBank, they are most closely related to <it>Strelkovimermis spiculatus</it>.</p> <p>Conclusions</p> <p>To our knowledge, this is the first report of mermithids from adult <it>Anopheles</it> mosquitoes in Senegal. The mermithid appears to infect <it>Anopheles</it> mosquitoes that develop in diverse larval habitats. Although maximum parsimony analysis determined the mermithid was closely related to <it>Strelkovimermis spiculatus</it>, several characteristics of the mermithid were more similar to the <it>Empidomermis</it> genus. Future mermithid isolations will hopefully allow: formal taxonomic identification, laboratory colonization, determination of life history traits and species specificity, and characterize its usefulness as a biological control agent.</p