Glossina pallidipes is a haematophagous insect that serves as a cyclic transmitter of trypanosomes causing African Trypanosomiasis (AT). To fully assess the role of G. pallidipes in the epidemiology of AT, especially the human form of the disease (HAT), it is essential to know the microbial diversity inhabiting the gut of natural fly populations. This study aimed to examine the diversity of G. pallidipes fly gut bacteria by culture-dependent approaches.
Results
113 bacterial isolates were obtained from aerobic and anaerobic microorganisms originating from the gut of G. pallidipes. 16S rDNA of each isolate was PCR amplified and sequenced. The overall majority of identified bacteria belonged in descending order to the Firmicutes (86.6%), Actinobacteria (7.6%), Proteobacteria (5.5%)and Bacteroidetes (0.3%). Diversity of Firmicutes was found higher when enrichments and isolation were performed under anaerobic conditions than aerobic ones. Experiments conducted in the absence of oxygen (anaerobiosis) led to the isolation of bacteria pertaining to four phyla (83% Firmicutes, 15% Actinobacteria, 1% Proteobacteria and 0.5% Bacteroidetes, whereas those conducted in the presence of oxygen (aerobiosis) led to the isolation of bacteria affiliated to two phyla only (90% Firmicutes and 10% Proteobacteria). Phylogenetic analyses placed these isolates into 11 genera namely Bacillus, Acinetobacter, Mesorhizobium, Paracoccus, Microbacterium, Micrococcus, Arthrobacter, Corynobacterium, Curtobacterium, Vagococcus and Dietzia spp.which are known to be either facultative anaerobes, aerobes, or even microaerobes.
Conclusion
This study shows that G. pallidipes fly gut is an environmental reservoir for a vast number of bacterial species, which are likely to be important for ecological microbial well being of the fly and possibly on differing vectorial competence and refractoriness against AT epidemiology.
We investigated the dynamics of Glossina spp. and their role in the transmission of trypanosomiasis in the sleeping sickness endemic Serengeti ecosystem, northwestern Tanzania. The study investigated Glossina species composition, trap density, trypanosome infection rates, and the diversity of trypanosomes infecting the species. Tsetse were trapped using monopyramidal traps in the mornings between 06:00 to 11:00 and transported to the veterinary laboratory in Serengeti National Park where they were sorted into species and sex, and dissected microscopically to determine trypanosome infection rates. Age estimation of dissected flies was also conducted concurrently. Tsetse samples positive for trypanosomes were subjected to PCR to determine the identity of the detected trypanosomes. Out of 2,519 tsetse trapped, 1,522 (60.42%) were G. swynnertoni, 993 (39.42%) were G. pallidipes, three (0.12%) were G. m. morsitans, and one (0.04%) was G. brevipalpis. The trap density for G. swynnertoni was between 1.40 and 14.17 while that of G. pallidipes was between 0.23 and 9.70. Out of 677 dissected G. swynnertoni, 63 flies (9.3%) were infected, of which 62 (98.4%) were females. A total of 199 G. pallidipes was also dissected but none was infected. There was no significant difference between the apparent densities of G. swynnertoni compared to that of G. pallidipes (t = 1.42, p = 0.18). Molecular characterization of the 63 infected G. swynnertoni midguts showed that 19 (30.2%) were trypanosomes associated with suid animals while nine (14.3%) were trypanosomes associated with bovid animals and five samples (7.9%) had T. brucei s.l genomic DNA. Thirty (47.6%) tsetse samples could not be identified. Subsequent PCR to differentiate between T. b. brucei and T. b. rhodesiense showed that all five samples that contained the T. brucei s.l genomic DNA were positive for the SRA molecular marker indicating that they were T. b. rhodesiense. These results indicate that G. swynnertoni plays a major role in the transmission of trypaniosomiasis in the area and that deliberate and sustainable control measures should be initiated and scaled up. 相似文献
Glossina pallidipes is a haematophagous insect that serves as a cyclic transmitter of trypanosomes causing African Trypanosomiasis (AT). To fully assess the role of G. pallidipes in the epidemiology of AT, especially the human form of the disease (HAT), it is essential to know the microbial diversity inhabiting the gut of natural fly populations. This study aimed to examine the diversity of G. pallidipes fly gut bacteria by culture-dependent approaches.
Results
113 bacterial isolates were obtained from aerobic and anaerobic microorganisms originating from the gut of G. pallidipes. 16S rDNA of each isolate was PCR amplified and sequenced. The overall majority of identified bacteria belonged in descending order to the Firmicutes (86.6%), Actinobacteria (7.6%), Proteobacteria (5.5%)and Bacteroidetes (0.3%). Diversity of Firmicutes was found higher when enrichments and isolation were performed under anaerobic conditions than aerobic ones. Experiments conducted in the absence of oxygen (anaerobiosis) led to the isolation of bacteria pertaining to four phyla (83% Firmicutes, 15% Actinobacteria, 1% Proteobacteria and 0.5% Bacteroidetes, whereas those conducted in the presence of oxygen (aerobiosis) led to the isolation of bacteria affiliated to two phyla only (90% Firmicutes and 10% Proteobacteria). Phylogenetic analyses placed these isolates into 11 genera namely Bacillus, Acinetobacter, Mesorhizobium, Paracoccus, Microbacterium, Micrococcus, Arthrobacter, Corynobacterium, Curtobacterium, Vagococcus and Dietzia spp.which are known to be either facultative anaerobes, aerobes, or even microaerobes.
Conclusion
This study shows that G. pallidipes fly gut is an environmental reservoir for a vast number of bacterial species, which are likely to be important for ecological microbial well being of the fly and possibly on differing vectorial competence and refractoriness against AT epidemiology.
