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Background: Tsetse flies are cyclical vectors of African trypanosomiasis (AT). The flies have established symbiotic associations with different bacteria that influence certain aspects of their physiology. Vector competence of tsetse flies for different trypanosome species is highly variable and is suggested to be affected by bacterial endosymbionts amongst other factors. Symbiotic interactions may provide an avenue for AT control. The current study provided prevalence of three tsetse symbionts in Glossina species from Cameroon, Chad and Nigeria. Results: Tsetse flies were collected and dissected from five different locations. DNA was extracted and polymerase chain reaction used to detect presence of Sodalis glossinidius, Spiroplasma species and Wolbachia endosymbionts, using species specific primers. A total of 848 tsetse samples were analysed: Glossina morsitans submorsitans (47.52%), Glossina palpalis palpalis (37.26%), Glossina fuscipes fuscipes (9.08%) and Glossina tachinoides (6.13%). Only 95 (11.20%) were infected with at least one of the three symbionts. Among infected flies, six (6.31%) had Wolbachia and Spiroplasma mixed infection. The overall symbiont prevalence was 0.88, 3.66 and 11.00% respectively, for Sodalis glossinidius, Spiroplasma species and Wolbachia endosymbionts. Prevalence varied between countries and tsetse fly species. Neither Spiroplasma species nor S. glossinidius were detected in samples from Cameroon and Nigeria respectively. Conclusion: The present study revealed, for the first time, presence of Spiroplasma species infections in tsetse fly populations in Chad and Nigeria. These findings provide useful information on repertoire of bacterial flora of tsetse flies and incite more investigations to understand their implication in the vector competence of tsetse flies. [ABSTRACT FROM AUTHOR]

Tsetse flies are the exclusive biological vectors of African trypanosomes in Africa, which are estimated to cover about 80% of the country’s total area, hindering rearing of livestock and creating health risk to humans as well. This study was performed to determine the sex and species composition of tsetse flies from selected communities of Kagarko Local Government Area, Kaduna State, Nigeria. Sampling of flies was done using standard biconical traps according to the method of Challier and Larvessiere and were sorted into sex and species using morphological distinctions as described by Leak. The study was carried out for four (4) months, during which forty seven (47) tsetse flies were caught, 16 (34.04%) were male and 31(65.96%) were female and all forty seven (47) flies were members of the Glossina palpalis palpalis. The abundance of more female flies supports the fact that they live longer, go out more frequently in search of blood meal due to reproductive requirements and the presence of only Glossina palpalis palpalis implies that it is the dominant species, hence, transmission of trypanosomiasis as Glossina palpalis palpalis are the major vectors of trypanosomiasis in Nigeria. [ABSTRACT FROM AUTHOR]

The study on tsetse flies and trypanosomes was carried out within Kagarko Local Government Area, Kaduna State to determine the prevalence and density of tsetse flies and their infection rate in the study area. The study was carried out between March and May, 2018. A total of four sampling sites were considered, these include Katugal, Kubacha Forest Reserve, Maganda Kagarko and Fantaki. Seven (7) traps were deployed in each sampling site for tsetse flies trapping, and a total of twenty eight (28) biconical traps were used during the study period. One hundred and forty four (144) biting flies were caught, these include one hundred and thirty (130) tsetse flies and fourteen (14) other biting flies. Twenty one (21) non teneral tsetse flies were dissected using dissecting pins and microscope. All the tsetse flies caught were Glossina palpalis, this comprises of 76 males and 54 females. The tsetse flies mean apparent density was 1.55 flies per trap per day (F/T/D). The result of tsetse flies dissection indicated 2(9.5%) flies were infected with trypanosome infection and T. vivax was known to be the infecting trypanosome. Both male and female tsetse fly had equal infection rate of 4.8%. This survey revealed data on tsetse flies abundance and other biting flies with potential as mechanical transmitters of T. vivax, which also indicates the possibility of trypanosomiasis in the study area. Therefore, studies to determine trypanosome prevalence in human and livestock should be conducted in the area for active trypanosomiasis control programs. [ABSTRACT FROM AUTHOR]

Introduction: Glossina spp. (Glossinidae), Tabanus spp. (Tabanidae), Ancala spp. (Tabanidae), Atylotus spp. (Tabanidae) and Stomoxys spp. (Muscidae) are important transmitting vectors of African animal trypanosomosis in sub-Saharan Africa. There is paucity of information on the distribution and identification of these flies in cattle settlements in southwest Nigeria. Methods: The distribution patterns, genetic variations and diversities of dipteran flies in southwest Nigeria were described and identified using morphological and molecular analysis of the 28S rDNA gene. Results: Of the 13,895 flies examined morphologically between April 2016 and March 2017, tabanids were identified [Tabanus (0.34%), Ancala (0.03%), Atylotus (0.01%), Haematopota (0.014%) and Chrysops (0.11%)]. Two stomoxyine species were identified; Stomoxys niger niger Macquart (45.30%) and Stomoxys calcitrans Linnaeus (17.29%) and two Glossina spp. namely; Glossina p. gambiense Vanderplank, 1911 (0.46%) and Glossina tachinoides Westwood (0.51%) were identified. The identities were further confirmed in a BLAST search using their nucleotide sequences. The median-joining network of the 28S rDNA gene sequences indicated that fly species examined were genetically distinct. The apparent density of all the trapped flies was highest at a mean temperature of 26–28 ℃, humidity > 80% and rainfall of 150–220 mm/month. The distribution of flies was observed to increase as vegetation increased in density and decreased in areas with relatively high human population density (> 100/km2). Conclusions: The population indices of the 28S rDNA gene of the flies suggest that analysis of nuclear DNA fragments may provide more information on the molecular ecology of these flies. Characterising fly species and assessing their impact are essential in distribution and monitoring AAT spread. [ABSTRACT FROM AUTHOR]

Significant increases in human and livestock populations coupled with agricultural practices have changed the socioeconomic perspectives of livestock diseases. Evaluating the socioeconomic impact of bovine trypanosomosis and its vectors (Glossina, Tabanus and Stomoxys) from the perspective of the livestock owners is of great significance. Participatory rural appraisal was conducted among 209 livestock owners (focus groups) to determine the behavioural practices of animal husbandary to bovine trypanosomosis. In Nigeria, common Trypanosoma species found in cattle are Trypanosoma vivax, Trypanosoma congolense and Trypanosoma brucei. Trypanosomosis peaks were reported by owners to be in the months of March-August. A total of 70.8% (95%CI 64.32-76.56%) cattle owners perceived trypanosomosis as a major disease in their herd, 13.4% (95%CI 9.43-18.68%) practiced transhumance in the wet season and 93.9% (95%CI 88.58-96.92%) make use of trypanocides, and approximately US$ 8.4 million is spent annually on trypanocides in southwest Nigeria livestock industry. About 60.5% (95%CI 51.84-68.48) make use of insecticides against transmitting vectors, and only 1.9% (95%CI 0.75-4.82%) have ever heard of any form of government intervention scheme. Estimated losses ≥ US$ 426 (80-100% loss) can be incurred on a single animal depending on the size and market value. There is significant increase (16.2%, 95%CI 11.15-23.00%, P < 0.05) in the mortality rate of bovine trypanosomosis when compared to other livestock diseases. It will therefore be useful to involve the livestock owners with devising new and integrated measures for reducing the impact of this trypanosomosis.

Vector control is important to effectively prevent trypanosomiasis. Therefore, alighting and feeding responses of trypanosome-transmitting vectors were conducted in Nigeria. The aim of this study was to assess the landing preference, level of fly annoyance on cattle, and feeding behavior by direct observation of cows, bulls, and calves. The percentage of Glossina species, Tabanus species, and stomoxyine that fed on cattle blood after landing varied according to the age and sex of the cattle host. Although most flies left the cattle host before completing their meal because of host defensive behaviors, an average of 78, 19.6, and 10.2% of Glossina, Tabanus, and stomoxyines, respectively, were fully engorged. The longest mean feeding time was observed in Glossina. Over more than 90% of Glossina spp. landed on the belly and legs. Most Tabanus spp. (85%) also landed on the belly and legs while Tabanus par Walker (Diptera: Tabanidae) often landed on the back (45%). Half of Stomoxys species landed on the head and neck. Vector flies' feeding success varied according to cattle host age and was negatively correlated with defensive host behaviors and apparent fly density. Hence, fly defensive behaviors contribute to trypanosomiasis dynamics in a cattle herd, and expended energy from defensive behaviors could adversely affect productivity.

Despite extensive attempts over many decades to control African Animal Trypanosomiasis (AAT) across the tsetse fly belt of Nigeria, AAT persists as major animal health problem causing severe morbidity and mortality in livestock. The large agricultural losses in turn have severe adverse impacts on sustainable agricultural development. Despite this, in the past 50 years there have been no significant national control programs against AAT. This review explores the history of AAT control in Nigeria, examining the successes and failures in measures adopted in Nigeria to control AAT and the changing disease epidemiology., (Copyright © 2018 Elsevier B.V. All rights reserved.)

A study was made of village goat and sheep production systems in the humid tropical zone of south-west Nigeria. A summary of the herd and flock population dynamics is given followed by a discussion of the importance of goat and sheep production in southern Nigeria and suggestions for methods of improvement. The problems of livestock production in areas of endemic trypanosomiasis are discussed and it is concluded that, where cattle are excluded due to this disease and where human population pressure is high, goats and sheep have a continuing and increasing role to play in providing meat for the expanding human populations.

Human infection with Trypanosoma gambiense in the Gboko endemic area was first reported in May, 1974 although T. gambiense sleeping sickness had been present there since the turn of the century. The disease is associated with the presence of the tsetse Glossina tachinoides and Glossina palpalis which is plentiful and widespread throughout the division as well as in thickets along the streams in the area. No successful attempt has been made to control the tsetse vector in the Division. The incidence and geographical distribution of cases of T. gambiense sleeping sickness in the Gboko area are described in this report. Cases were treated with Antrypol Tryparsamide mixture and Mel B. The highest number of cases of infection is usually picked up just before the start of the rains in early April. It is suggested that, for meaningful control of the disease a quick method should be devised to rid the area of the insect vector.

During the last decade, an increasing number of instances have been noted of tsetse flies occupying unusual, and often man-made, habitats. Recently, some aberrant populations have become important, either because they have drawn attention to new aspects of trypanosomiasis transmission or because they have necessitated modifications of established tsetse control methods.From observations made on atypical tsetse populations in Nigeria, the author has classified the various types of intra-specific behaviour patterns observed and offers an interpretation. At least 1 species, Glossina tachinoides, is normally extremely versatile ecologically but some populations are now so adapted to man-made habitats that they can probably be explained only on the basis of subspeciation. Some populations of other species of tsetse, such as G. fuscipes and G. morsitans, seem also to be involved in atypical behaviour patterns.The investigations emphasize the need to clarify the role of tsetse flies in the epidemiology of the trypanosomiases and the suitability of established tsetse control measures in areas where the pattern of vector behaviour differs from that of more conventional foci of disease transmission. Much of the African continent is rapidly changing to meet the needs of large human populations and it is therefore envisaged that many more tsetse populations will become adapted to habitats dominated by man, as the only alternative to extinction, so that the problem of trypanosomiasis may remain as great, or become greater, in the future.

The author reviews recent ecological research on tsetse flies in East Africa and Northern Nigeria, particularly in connexion with the flies' sensory reactions, and stresses the importance of an accurate knowledge of their daytime and night-time resting-sites and of identifying the sources of their blood meals in order to elucidate the reservoirs of trypanosomiasis. The epidemiology of the disease is considered in the light of studies of trypanosome infections in host and fly. The control of tsetse flies must be based on the practical application of ecological knowledge by methods involving either a direct attack upon the fly (such as trapping or the use of insecticides) or an indirect attack (such as bush clearing or game destruction to eliminate the fly's habitat or food supply); these methods are dealt with in some detail. The author concludes with a discussion of modern trends in research, and a number of lines of research are suggested.

With the advent of modern persistent insecticides, it has become possible to utilize some of the knowledge that has accumulated on the ecology and bionomics of Glossina and to devise more effective techniques for the control and eventual extermination of these species.The present article, based on experience of the tsetse fly problem in Northern Nigeria, points out that the disadvantages of control techniques-heavy expenditure of money and manpower and undue damage to the biosystem-can now largely be overcome by basing the application of insecticides on knowledge of the habits of the particular species of Glossina in a particular environment. Two factors are essential to the success of a control project: the proper selection of sites for spraying (the concept of restricted application) and the degree of persistence of the insecticide used. Reinfestation from within or outside the project area must also be taken into account.These and other aspects are discussed in relation to experience gained from a successful extermination project carried out in the Sudan vegetation zone and from present control activities in the Northern Guinea vegetation zone.