Biomedical subjects

E J Asimeng

Publications and source records attributed to E J Asimeng.

5 recordsLinked to original sources

PubMed1993

Effect of rice husbandry on mosquito breeding at Mwea Rice Irrigation Scheme with reference to biocontrol strategies.

A study was carried out at Mwea Rice Irrigation Scheme, Kenya, to assess the impact of rice husbandry on mosquito breeding and identify indigenous biocontrol agents with potential for controlling mosquito breeding in the scheme. The study established a close relationship between the schedule of the farming practices (particularly the flooding phase) and mosquito breeding. Two groups of agents, entomopathogenic bacteria (Bacillus thuringiensis var. israelensis) and larvivorous fish, were identified. Laboratory evaluation of the agents produced encouraging results. The bacterial isolates showed broad-spectrum larvicidal potency against Anopheles, Culex and Aedes mosquito larvae and 2 of the fish species, Tilapia zilli and Oreochromis niloticus, demonstrated a strong predation for a mosquito larval diet. To facilitate their use in effective biocontrol strategies, the agents would require further evaluation under field conditions.

Aedes↗

PubMed1992

Isolation of mosquito-toxic bacteria from mosquito-breeding sites in Kenya.

A large number of source materials were collected for isolating entomopathogenic bacteria from larval mosquito habitats in Kirinyaga District, Kenya. Mosquito-toxic bacteria were included among the numerous types of microorganisms isolated from the habitats. The pathogenic isolates shared common structural characteristics; they were gram-positive, spore-forming bacilli that produced parasporal inclusions conferring broad-spectrum larvicidal activity against Anopheles, Culex and Aedes mosquitoes. Based on structural and growth characteristics, coupled with larvicidal activity, the pathogenic isolates were tentatively identified as variants of Bacillus thuringiensis. Although the collection consisted of a variety of items including soil, silt and mud, the most productive materials were larval bodies. Using healthy mosquito larvae held in a fully permeable plastic bottle, a baiting technique was developed as a means of recovering bacteria from the environment.

Aedes↗

PubMed1991

Preliminary account of the phenology of some Nigerian savanna phlebotomine sandflies (Diptera: Psychodidae).

A total of 1,705 sandflies was collected by sticky trap from the Guinea savanna of northern Nigeria to determine their seasonal and spatial fluctuations in abundance. Adult sandflies persisted throughout the year, but the highest diversity and abundance were recorded at the end of the rainy season. Females were collected more frequently than were males. The species collected in order of decreasing abundance were Sergentomyia antennata Newstead, S. bedfordi Newstead, S. africana Newstead, S. schwetzi Adler, Theodor & Parrot, S. affinis Theodor, S. adleri Theodor, S. clydei Sinton, S. simillima Newstead, S. buxtoni Theodor, S. christophersi Sinton, and Phlebotomus rodhaini Parrot. Sandfly abundance was greater near rocky terrain (Dumbi inselberg) and on an animal farm than on the open plains and in a residential area. Known vectors of leishmaniasis were not collected, despite the report of human cases in the study area.

Animals↗

PubMed1990

The distribution of phlebotomine sandflies (Diptera: Psychodidae) in northern Nigeria.

A survey was carried out in Northern Nigeria to determine the distribution of the species of phlebotomine sandflies in the major vegetation zones: Sahel, Sudan, Northern Guinea Savanna, and Southern Guinea Savanna. The two Old World Genera, Phlebotomus and Sergentomyia, are both represented in the study area, with an overwhelming preponderance of Sergentomyia species; about 99% of the entire collection (12, 951 specimens) belong to the genus Sergentomyia. Out of the thirteen species identified, two belong to the genus Phlebotomus: Phlebotomus duboscqi and Phlebotomus rodhaini; the remaining eleven are species of the genus Sergentomyia grouped under series simillama and two subgenera (antennata, bedfordi, africana, schwetzi, ingrami, and buxtoni in the subgenus Sergentomyia and affinis, adleri, clydei and christophersi under Sintonius subgenus. P. duboscqi occurs in Sahel and Sudan zones whereas P. rodhaini exists mainly in the Guinea Savanna (north and south). In general, the distribution of the species in the subgenus Sergentomyia (particularly antennatta, bedfordi, africana, and schwetzi) cuts across all the four vegetation zones. The least common species, simillima, was found only in the North Guinea Savanna. Members of the Sintonius group were obtained from Sudan and Northern Guinea Savanna zones.

Animals↗

PubMed1988

Comparative study of sandfly trapping techniques.

Three test oils (Castor oil, Groundnut oil and Engine oil) were used in sticky traps with the view of evaluating their relative efficiency in forming adhesive surfaces for collecting phlebotomine sandflies. Although engine oil exhibited maximum efficiency, the performance of all the three oil types compared favourably with one another both quantitatively and qualitatively. The engine oil had additional advantages over the other oils in being less expensive and not attractive to vertebrates (rodents, lizards) which interfere with the performance of sticky traps. Termite hills and rock crevices provided important sources for collecting sandflies in the study area. The specimens collected consisted of 2 Phlebotomus and 8 Sergentomyia species identified as Phlebotomus duboscqi, P. rodhaini, Sergentomyia antennata, S. bedfordi, S. schwetzi, S. ingrami, S. christophersi, S. affinis, S. clycdei and S. africana.

Animals↗