Trypanosome Prevalence in Pigs and Tsetse Flies from Jomoro District in the Western Region of Ghana

Abstract

The study was carried out from October to November 2013 in Jomoro district of the Western Region of Ghana to assess the prevalence of trypanosomes in pigs and tsetse flies. Besides, the study identifies tsetse fly species and their apparent density in the study area. The methods employed during the study were molecular technique and microscopy of stained blood smears for parasitological study. Entomological surveys were also conducted using a total of 16 un-baited biconical traps for the collection of tsetse flies. A total of 300 pigs were randomly selected from the study population and examined for the presence of trypanosomes. The PCV value of each animal was also measured using haematocrit reader. From the entomological survey, DNA was isolated from 300 flies and subjected to PCR for trypanosome detection and identification. An overall prevalence of trypanosomes in the study area was 4.33% and 0.77% for pigs and tsetse flies respectively. None of the blood samples was positive for the presence of trypanosome species by microscopy of stained blood smears. Out of positive cases, mixed infection between Trypanosoma congolense Forest and Trypanosoma vivax showed the highest prevalence (46.15%) of trypanosome species followed by Trypanosoma vivax (15.38%), while of Trypanosoma congolense and a mixed infection of Trypanosoma congolense, Trypanosoma vivax and Trypanosoma brucei gambiense were the least with (7.70%) each. The study also demonstrated no variations in prevalence among different age groups and between both sexes which were statistically insignificant (p > 0.05). The prevalence rate in good and poor body conditioned animals were 1.9 % and 20 %, respectively with a statistical significant difference (P < 0.05) among them. Mean packed cell volume (PCV) of parasitaemic pigs (29.33%) was significantly (P< 0.05) lower than that of aparasitaemic pigs (37.75%). The entomological survey showed that Glossina palpalis palpalis was the only tsetse species with fly apparent density of 18.36 fly/trap/day found in the study area. Diagnosis of trypanosomiasis in tsetse or domestic livestock is a basic requirement for epidemiological studies as well as for planning and implementing control operations. Therefore, the results of this study should be used to define the strategy of disease control in places where tsetse and trypanosomiasis challenge were reported. Although the present study revealed low prevalence, implementing control of trypanosomiasis with an integrated approaches have paramount importance in the study sites.