Disease and vector constraints affecting cattle production in pastoral communities of Ssembabule district, Uganda

C P Otim, M Ocaido*, N M Okuna, J Erume*, C Ssekitto, R Z O Wafula*, D Kakaire, J Walubengo, A Okello, A Mugisha* and J Monrad**

Livestock Health Research Institute (LIRI), P. O. Box 96, Tororo, Uganda,
liridir@hotmail.com
*Faculty of Veterinary Medicine, Makerere University, P. O. Box 7062, Kampala, Uganda,
mocaido@yahoo.com
**Royal Veterinary and Agricultural University, Dyrlaegevej 100, DK-1870 Frederiksberg C, Denmark
jm@kvl.dk

Abstract

A survey was carried out to determine the disease and vector constraints to cattle production in pastoral communities settled in three villages of two sub-counties in Ssembabule district. After sensitising farmers, 454 cattle randomly selected in three villages were sampled for blood parasite infections (antibody ELISA serology and direct parasite detection), for gastrointestinal parasites and for tick infestation. Tsetse exposure was assessed by trapping.

The prevalence of trypanosomosis was low on direct trypanosome detection in blood samples (0.7 %) as well as on serology (6.7 %), and no tsetse flies were encountered. Three head of cattle (0.7%) were infected with Theileria parva, the cause of East Coast Fever (ECF). However, serological analysis for antibodies against Theileria parva revealed a very high prevalence of exposed animals (93.3%). Three head of cattle (0.7%) were further found infected with Anaplasma marginale, the cause of anaplasmosis (gall sickness). In addition, 59.1% of the cattle examined were shedding worm eggs. Meanwhile 28.7% of the sera of cattle tested using Rose Bengal rapid agglutination test were positive for bovine brucellosis caused by Brucella abortus.

A relatively high tick infestation was demonstrated. Rhipicephalus appendiculatus was found to be the most abundant species with a mean tick count per head of cattle of 3.7 ± 0.28, followed by Rhipicephalus evertsi and Amblyomma variegatum with mean tick counts per head of cattle of 0.51 ± 0.3 and 0.24 ± 0.012, respectively. In a preceding questionnaire survey the cattle owners in Ssembabule district had pointed to trypanosomosis as their most important disease problem. This laboratory-based diagnostic survey, however, revealed that ticks, tick-borne diseases and brucellosis were the real major constraints to cattle production in that district, while tsetse and trypanosomosis appeared to be of little or no importance.

It is concluded that planning of disease control measures in a given area should depend on laboratory-based diagnostic observations rather than on a questionnaire survey.

Keywords: cattle production, Uganda, pastoral agro-pastoral system, ticks, tick-borne diseases, tsetse, trypanosomosis, helminthosis, assessment of impact, diagnostic survey

Introduction

Most of the sub-Saharan African range lands are inhabited by pastoralists and agro-pastoralists who live on the edge of disaster and are always amidst of poverty (Teer 1986). They are always at the mercy of insects, diseases, predators, drought, floods and other natural disasters. Their livelihoods are totally dependent on livestock. Among the major constraints to livestock productivity in pastoral and agro-pastoral areas in Uganda are ticks and tick-borne diseases (TBDs) (Ocaido et al 1996, Moran 1996) and tsetse flies and trypanosomosis (Magona et al 1998). Of the diseases caused by ticks and TBDs, East Coast Fever (ECF, theileriosis), anaplasmosis, babesiosis and cowdriosis are the most important and widespread (Otim 2000). Tsetse flies infest about 41% of the entire landmass of Uganda and 70 % of livestock grazes under risk of trypanosomosis, of which 40% graze under high trypanosome challenge (Ndyabahinduka 1993). TBDs and trypanosomosis continue to impede livestock productivity in most parts of Uganda because of continued persistence and expansion of the distribution of tsetse flies and trypanosomosis outbreaks, development of drug-resistant parasites, existence of suitable climate for ticks and inadequate control of both ticks and tsetse flies. A Participatory Rural Appraisal (PRA) survey (Anonymous 1999) and a follow up socio-economic baseline survey (Nanyeenya 2000) highlighted the importance of ticks and TBDs, and tsetse flies and trypanosomosis in pastoral communities that inhabit Mawoogola county, Ssembabule district. Other diseases mentioned by the farmers were helminthosis, anaplasmosis, lumpy skin disease, liver fluke infection and ephemeral fever.

The PRA survey (Anonymous 1999), revealed that the farmers in Ssebambule district dewormed their animals regularly and spent a significant amount of their income in control of both trypanosomosis and ticks and TBDs. Trypanosomosis was controlled through prophylactic treatment using Samorin^â (isometamidium bromide) or Berenil^â (diminazene aceturate) while ticks and TBDs, were controlled by spraying cattle with acaricides. It was further pointed out that acaricides were applied in a haphazard manner. In most cases, they were applied at lower concentrations and more frequently than recommended by the producer (Okello-Onen 1995, Kaiser et al 1988, Floyd et al 1987).

In an attempt to determine the actual diseases and vectors prevalent in the area and remove the constraint of these diseases and vectors as well as evaluate the existing control programs, three villages in Ssembabule district were selected for study. This paper reports the status of cattle diseases and disease vectors in the three areas.

Description of the survey

Sensitisation and selection of farmers

Sensitisation was achieved through two meetings with farmers and extension workers. The farmers came from three villages, Kenkonge, Kyanika and Nakatabo, which belong to three different parishes located within two different sub-counties. Workshops were held with the farmers and objectives of the project were discussed with them. Ten farmers including male and female were selected randomly to participate in the project from each village during the course of the workshop with the help of extension workers. Later three sites were identified: site 1 in Kenkonge, site 2 in Kyanika, and site 3 in Nakatabo. One or two crushes were constructed at each of these sites.

Sampling and duration of study

Twenty head of cattle per herd (farmer) were randomly selected for examination. The majority of the cattle sampled were the local Ankole cattle; others were crosses, Friesians and a few Borans. Cattle were examined at all the three sites. Before handling their cattle, each farmer was questioned about the acaricide and anthelmintics they use and when they last used a trypanocide. The cattle were ear-tagged and examined for ticks. Ticks were collected from one side of the body on each animal. Particular attention was paid to predilection sites for each of the common species. Faecal samples were then collected, and blood samples were taken from the jugular or coccygeal veins into non-heparinised vacutainers for serum production. Blood was taken from all the identified cattle whereas faecal samples were collected randomly from half of the chosen cattle. The field collection of samples was conducted for two weeks, in November 2000.

Examination of samples

The standard ticks (number of engorged ticks per animal) were identified and counted. During sampling blood was also taken from each animal directly into a heparinised capillary tube and examined on the spot for trypanosomes by the buffy coat technique (BCT) as described by Murray et al (1979). The packed cell volume (PCV) was also measured for each animal. Thin blood smears were made and examined for haemoparasites in the laboratory under oil immersion following Giemsa stain. Serum samples were separated from clotted blood and stored at -20⁰ C until analysed by ELISA for antibodies against Trypanosoma spp and Theileria parva. Sera were also analysed for antibodies against brucellosis by the Rose Bengal rapid agglutination test.

For faecal examination a quantitative flotation method (McMaster) was applied for detection of nematode eggs, cestode eggs and coccidia oocysts, while a simple sedimentation method was used for detection of trematode eggs.

Tsetse trapping

Tsetse traps were set up to assess the risk of tsetse exposure. Three different tsetse traps: biconical, pyramidal and mono-screen were used in the area. At each site, a total of 15 traps, 5 of each type, were deployed and left in position for 72 hours. Traps were checked for flies twice a day.

Results

Altogether 23 farmers were selected, of whom five farmers were from Kenkonge, nine from Kyanika and nine from Nakatabo. Five of these farmers (21.7%) were women. A total of 454 cattle were identified and tagged for examination. Results of PCV analysis revealed that cattle in Kenkonge had a mean PCV of 34.7±0.83; in Kyanika 33.0±0.81 and in Nakatabo 35.8±1.76.

Ticks and tick-borne diseases

All the farmers (n=5) from Kenkonge, 8 (n=9) from Kyanika and 8 (n=9) from Nakatabo used Amitraz^â (N-methylbis-(2,4 xylyliminomethyl)-amin) for the tick control. However, only 1 (n=9) from Kyanika used Tsetse tick^â and 1 (n=9) from Nakatabo used Renegade^â (alphacypermethrin).

The most abundant tick species recovered on cattle was Rhipicephalus appendiculatus with a mean of 3.7±0.28 ticks per head. The other ticks recovered were Rhipicephalus evertsi and Amblyomma variegatum with mean tick numbers of 0.51±0.3 and 0.024±0.012 per head, respectively. The variation of mean tick counts per head of cattle per site is shown in Table. 1.

When blood was examined for TBD parasites, three were positive for Theileria parva and three for Anaplasma marginale infection out of 454 cattle, a prevalence rate of 0.7% in each case. The prevalence of TBD's in cattle from various villages is shown in Table 2. Meanwhile the examination of sera by ELISA for exposure to Theileria parva, revealed 93.3% of all the cattle had antibodies to Theileria parva.

Tsetse and trypanosomosis

None of the farmers in all the three study sites had used any trypanocidal drugs. No tsetse flies were caught in traps. Only biting flies of the genera Haematopota and Stomoxys were caught (Table 3).

The results of blood examination by BCT revealed that in Kenkonge, one animal was positive for Trypanosoma congolense; 0% in Kyanika and 1.1% (n=2) in Nakatabo. The prevalence of antibodies against trypanosomes was 5% for Kenkonge, 2.5% for Kyanika and 12.5% for Nakatabo. The overall antibody prevalence was 6.7%.

Helminthosis

All farmers were found to be conscious of helminthosis, using albendazole, Levafas^Ò(levamisole) or Nilzan^Ò(levamisole-oxyclosanide combination) for their control. Examination of faecal samples revealed nematode eggs (strongyle type or Strongyloides eggs) and fluke eggs of the genera Paramphistomum and Fasciola. No cestode eggs were detected. The overall prevalence of worm egg excreting animals (excreters) was 59.1%, of which the majority were excreting nematode eggs (Table 4).

Brucellosis

Forty-one (41) sero-positive cases for antibodies against Brucella abortus were detected amongst 143 cattle examined indicating brucellosis prevalence rate of 28.7%.

Discussion

The findings from the PRA survey (Anonymous 1999) and those from the socio-economic study (Nanyeenya 2000), showed that trypanosomosis was considered to be one of the major disease constraints to cattle production in Ssembabule district. In opposition to that, our laboratory-based diagnostic survey revealed that the established prevalence of trypanosomosis in the study area was below 1.0% and the only species detected was Trypanosoma congolense.

The owner of the trypanosome positive cow in site 1 (Table 1) disclosed that the animal was purchased outside the study area. Therefore, the cow could have contracted the infection outside the study area. The owners of the other two trypanosome positive cattle identified in site 3 could not be contacted to ascertain the origin of the cattle. In any case, during dry seasons, pastoralists in this area regularly move out of the district to look for grazing and water for their livestock. It is noteworthy that cattle in site 3, where two cases of trypanosomosis were diagnosed, had the highest mean PCV (35.8%) followed by mean PCV of cattle in site 1 (34.7%), where one case of trypanosomosis was diagnosed. The mean PCV of cattle in Site 2 (33.0%), where no case of trypanososmosis was diagnosed, was the lowest. This suggests that in the study area, mean PCV had no value in predicting presence of trypanosomosis as would be expected in an area under trypanosomosis challenge. The high PCV of more than 30 % in all the study area shows that the cattle were generally in good bodily condition.

Most important was the low antibody prevalence against trypanosomes (6.7%), indicating that few animals had been exposed to trypanosome challenge. Furthermore, there was no evidence of the presence of tsetse flies in the area (Table 3). Failure to catch any tsetse flies indicated that either the area surveyed was indeed free of tsetse flies, although it is theoretically possible that the density of the existing tsetse population was so low that longer trapping period (over 72 hours), or trapping with more effective traps would be needed to detect it. The infected animals might also have been infected from other places where the animals go in search of pasture and water, and there might be a critical tsetse habitat within the study area providing resource during the dry season where all animals congregate. In spite of the obvious limitations of the tsetse survey carried out in this study, it appears that bovine trypanosomosis is not an important problem in these pastoral communities, particularly due to the low antibody prevalence.

As regards ticks and TBDs, farmers at all the three sites were found to be relying largely on Amitraz^Ò for tick control. This is quite different from what was obtaining earlier in 2000 when this study was being planned. This indicates that farmers in the area frequently change the acaricide they use probably due to economics in terms of use of relatively cheaper acaricides.

The high Theileria parva antibody prevalence (93.3%) shows that almost all the cattle are exposed to Theileria parva challenge hence likely to have attained some sort of endemic stability. Despite the extensive indiscriminate use of acaricides, a significant level of tick infestation (Table 1) was found especially so with Rhipicephalus appendiculatus. The TBD parasites encountered were Theileria parva and Anaplasma marginale, the causes of ECF and Bovine Anaplasmosis respectively. These data show that TBDs form a risk to the cattle in the study area and calls for effective control methods such as those designed for Burundi (Kaiser et al 1988) and Zimbabwe (Floyd et al 1987).

On the other hand, the level of helminthosis detected in the present survey seemed relatively low in terms of prevalence and faecal egg counts. However, the animal material of this survey was not ideal for assessment of helminthosis, because it included a large proportion of adult animals, which will usually excrete few or no eggs due to age-related and/or acquired immunity. This shows that helminthosis is a potential risk in the study area, but the real impact of it cannot be assessed from the present survey.

In our findings, the brucellosis prevalence based on ELISA detection of specific Brucella abortus antibodies was high, suggesting that brucellosis could be a major problem in Ssembabule. It is worth noting that one of the farmers prevented us from sampling a cow, which he intended to sell due to recurrent abortion.

Conclusion

The observations of the laboratory-based survey on disease constraints presented here revealed that ticks, tick-borne diseases (TBDs) and possibly brucellosis are much more important for cattle production than tsetse and tryponosomosis in Ssembabule district. These observations differ seriously from what was believed by the cattle owners as stated in a preceding Participatory Rural Appraisal (PRA) and a subsequent socio-economic baseline survey in the same district. Hence it is concluded that the impact of disease in livestock production may not be sufficiently assessed by indirect questionnaire surveys alone. Such surveys should always be followed up by a direct laboratory-based diagnostic disease survey, before costly specific disease control measures are introduced in local livestock populations.

Acknowledgements

We are grateful to Dr Ssali, Kakooza, Lule, Kankya, extention workers at the the Office of the District Veterinary Officer (DVO) and Dr Kalungi-Kawoya, DVO Ssembabule District, for their corporation and assistance in this work. Special thanks are due to DANIDA - LSRP for funding this study.

References

Anonymous 1999 Diagnostic survey report for Ssembabule district. Livestock Systems Research Program (LRSP), NARO-MUK. In Proceedings of LSRP Annual Review Workshop held at The Sunset Hotel International, Jinja, Uganda, 11^th to 12^th December, 67.

Floyd R B, Sutherst R W and Maywald G F 1987 Modelling tick management. III. Designing control of Rhipicephalus appendiculatus using T3HOST. Ticks and tick-borne Diseases, Canberra (R W Sutherst editor). ACIAR proceedings series No.17, ACIAR, 141-144.

Kaiser M N, Sutherst R W, Bourne A S, Gorissen L and Floyd R B 1988 Population dynamics of ticks and strategies for their control. Veterinary Medicine, 6, 199-122.

Magona J W, Okuna N M, Katabazi B K, Omollo P, Okoth J O and Mayende J S P 1998 Control of tsetse and animal trypanosomosis using a combination of tsetse trapping, pour-on and chemotherapy along Uganda-Kenya border. Revue d'Elevage et de Médecine Vétérinaire des Pays Tropicaux, 51, 311-315.

Moran M 1996 Epidemiology of Ticks and Tick-Borne Diseases in Uganda: Future research needs and priorities. In: Epidemiology of ticks and tick-borne diseases in Eastern, Central and Southern Africa (A D Irvin, J J Mcdermott and B D Perry editors.).Proceedings of a workshop held in Harare, 12^th-13^th March 1996. FAO, ILRI, Nairobi, Kenya, 83-87.

Murray M D, Clifford J and McIntyre W I M 1979Diagnosis of African Trypanosomiasis in bovine. Transactions of the Royal Society of Tropical Medicine and Hygiene., 73, 120-121.

Nanyeenya W 2000 Baseline study interim report of districts targeted for implementation of Livestock Systems Research Programs (LSRP) in Uganda . In Proceedings of LSRP Annual Review Workshop held at The Sunset Hotel International, Jinja, Uganda, 11^th to 12^th December.

Ndyabahinduka D G K 1993Uganda country report. The 22^nd International Scientific Council for Trypanosomosis Research and Control, Kampala, Uganda.

Ocaido M, Siefert L and Baranga J 1996 Disease surveillance in mixed livestock and game areas around Lake Mburo National Park in Uganda. South African Journal of Wildlife Research,26, 133-135.

Okello-Onen J 1995 Cattle tick population dynamics and the impact of tick control on the productivity of indigenous cattle under ranch conditions in Uganda. Ph.D thesis, Makerere University, Kampala, 236 pp.

Otim CP 2000 Advances in disease control: Ticks and tick-borne diseases. Uganda Journal of Agricultural Science, 5: 79 - 85.

Teer J G 1986 Compatibility and conflicts in uses of rangeland resources. In: Wildlife/ livestock interfaces on rangelands. Proceedings of a conference held at Taita Hills Lodge, Kenya 22-25, 1985 (S. MacMillan editor). Inter-African Bureau for Animal Resources, Nairobi, 5-9

Received 25 February 2004; Accepted 16 March 2004

Go to top