Biomedical subjects

J N Makumi

Publications and source records attributed to J N Makumi.

5 recordsLinked to original sources

PubMed2004

Identification of trypanosomes in Glossina pallidipes and G. longipennis in Kenya.

The polymerase chain reaction (PCR) was used to identify trypanosomes in Glossina pallidipes and G. longipennis caught in Kenya. Of 3826 flies dissected, 188 (4.9%) were parasitologically positive overall. The infection rate in G. pallidipes was 5.7% (187 of 3301 flies), but only one of 525 G. longipennis was infected (infection rate 0.2%). There was a higher infection rate in female G. pallidipes flies than male flies (chi(2) = 18.5, P < 0.001) and odds ratio = 2.5 (95% 1.6, 3.7). The infected flies were analysed by PCR using 10 sets of primers specific for species and subgroups within the subgenera Nannomonas, Trypanozoon and Duttonella. Of 188 parasitologically positive samples, PCR identified 137 (72.9%), leaving 51 (27.1%) non-identified. We recorded infection rates of 47.2% for Trypanosoma congolense savannah, forest and kilifi subgroups, 20.9% for T. simiae/T. simiae tsavo/T. godfreyi, 14.9% for T. brucei ssp. and 13.8% for T. vivax. Thirty-nine (26.7%) flies had mixed infections, with a minor association between T. congolense savannah/T. simiae tsavo/T. godfreyi (chi(2) = 6.93, d.f. = 1, P < 0.05). The relative proportion of each trypanosome species or subgroup varied between fly belts with T. congolense (all subgroups) being the most abundant and T. godfreyi the least. Statistical analysis showed that dissection method and PCR test classified infections independently (chi(2) = 10.5, d.f. = 1, P < 0.05 and kappa = 0.38). This study shows that pathogenic trypanosomes are widespread in all sampled testes fly belts with G. pallidipes as the main vector. Further, PCR test is more reliable in detecting and identifying trypanosomes than dissection method.

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PubMed2000

Control of Glossina longipennis (Diptera: Glossinidae) by insecticide-treated targets at Galana ranch, Kenya, and confirmation of the role of G. longipennis as a vector of cattle trypanosomiasis.

Glossina longipennis Corti was studied in Galana Ranch, Kenya over a four year period, in two areas (Tank E and Lali) where the species was abundant and other species were absent or scarce. There was active transmission of trypanosomiasis to cattle in both areas, the parasite species being Trypanosoma vivax Ziemann and T. congolense Broden. Mean infection rates of the G. longipennis were 1.1% and 0. 55% for T. vivax and T. congolense respectively at Tank E, and 0.88% and 0.15% at Lali. Experimental transmission studies showed that cattle in fly-proof enclosures challenged with wild G. longipennis collected from Galana became infected with both trypanosome species. A tsetse control operation in one area (Tank E) using targets impregnated with deltamethrin in an oil formulation reduced the population of G. longipennis by 98% over one year, despite evidence of re-invasion. Populations of G. longipennis in the other area (Lali) were relatively stable over the whole study period. The effect of tsetse control on the incidence of cattle trypanosomiasis at Tank E was less clear than that on tsetse numbers, probably due to the lack of a sustained reduction in tsetse numbers. However, a significant relationship was demonstrated between fortnightly incidence measurements and electric net catches of G. longipennis at Tank E. A further significant predictor of incidence was rainfall in the previous four to seven weeks. This study confirms the importance of G. longipennis as a vector of bovine trypanosomiasis in areas where it is the predominant tsetse present.

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PubMed1998

Activity patterns in Glossina longipennis: a field study using different sampling methods.

Studies n the daily activity of Glossina longipennis at Galana Ranch using a black odour-baited electrocuting target confirmed its crepuscular activity profile. Activity started at 05.00-05.30 hours and peaked at 06.00-06.30 hours, stopped by 09.00 hours, then started again at 17.00-17.30 hours with a peak at 18.30-19.00 hours, ceasing by 19.30 hours. Females made up 60% of the overall catch, and tended to arrive later than males. Other stationary sampling methods (trap, stationary ox) gave similar results. With the stationary methods, very few flies were caught outside the periods of peak activity (only 1.5% of the total between 09.00 and 17.00 hours); the ox was the only stationary bait to catch any flies between 10.00 and 16.00 hours. More flies were caught throughout the day at mobile baits (8.3% of the male and 2.3% of the female catch was taken between 09.00 and 17.00 hours). Mobile baits caught considerably more males than females (females were 17% of the catch). These males had on average higher fat and haematin reserves. Similar nutritional differences were not observed for females. There were fewer older females (ovarian category 3 or more) in mobile compared to stationary baits, and a lower proportion of the youngest males (wing fray category 1) at natural compared with artificial baits.

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PubMed1996

The role of cattle as hosts of Glossina longipennis at Galana Ranch, south-eastern Kenya.

Glossina longipennis were recorded visiting and engorging on cattle in an enclosure and on a single ox in a crush using transparent electrocuting nets in an incomplete ring. Of the total flies caught, 3-6% of males and 5-6% of females in the total catches were engorged (a feeding success rate of up to 16.6% and 12.6%, respectively, depending on assumptions made about the proportion which had an opportunity to feed). Direct observation of tsetse from an observation pit showed 57% landing on the front legs, 13% on the hind legs, and 11% on the belly of the host. The largest number of bloodmeals was taken from the front legs, although only 14% of landings there terminated in feeding; a higher proportion of the flies alighting on the hind legs and flank succeeded in feeding (28% and 21% respectively). Glossina longipennis were attracted to targets baited with ox odour from an underground pit in a dose-dependent manner. Odour of humans was much less attractive to G. longipennis than that of oxen (for equivalent biomass). Analysis of bloodmeal samples from tsetse caught in two sites on the ranch showed that G. longipennis preferentially feeds on suids, bovids and hippopotamus.

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PubMed1991

Trypanosoma vivax in Glossina palpalis gambiensis do not appear to affect feeding behaviour, longevity or reproductive performance of the vector.

Feeding behaviour of Glossina palpalis gambiensis Vanderplank infected with Trypanosoma vivax Ziemann was studied and compared with that of uninfected control tsetse. The parameters measured were: total number of probes into the ear-skin of rabbits; rate of bloodmeal engorgement; weight of freshly ingested blood; survival; and mean weight of pupae. The results showed that the rosettes of T.vivax parasites in the labrum did not interfere with the feeding behaviour of the vectors. Furthermore, mean survival of T. vivax-infected males was significantly higher (82.2 +/- 4.2 days) compared with that of uninfected ones (70.5 +/- 3.1 days). However, with the female tsetse, mean survival of those infected was lower (98.8 +/- 4.0 days) compared to the uninfected controls (102.2 +/- 5.6 days), but the difference was not significant. A few infected males and females lived a little longer than the uninfected ones. Fecundity of the female tsetse remained unaffected by the infection, and furthermore the mean weight of pupae from the infected females was not significantly different from that of pupae from the uninfected control group. Thus the physiology of pregnant female tsetse in terms of nourishment of intra-uterine larva was unaffected by T.vivax infection. Two successive probes into the skin of two different goats followed by feeding on a third goat by each of four infected tsetse resulted in successful transmission of the infection to eleven out of twelve goats. Thus probing alone into the skin of this host can result in the transmission of T.vivax infection.

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