The prevalence of serum antibodies to tick-borne infections in Mbale District, Uganda: The effect of agro-ecological zone, grazing management and age of cattle

Between August and October 2000, a cross-sectional study was conducted in smallholder dairy farms in Mbale District, Uganda to assess the prevalence of ticks and tick-borne diseases under different grazing systems and agro-ecological zones and understand the circumstances under which farmers operated. A questionnaire was administered to obtain information on dairy farm circumstances and practices. A total of 102 farms were visited and sera and ticks were collected from 478 animals. Sero-prevalence of tick-borne diseases was determined using an enzyme-linked immunoassay. Acaricides were used indiscriminately but the intensity of their use varied with the grazing system and zone. Cattle from different farms mixed for various reasons. During the dry seasons farmers have to get additional fodder from outside their farms that can result in importation of ticks. The prevalence of ticks and serum antibodies to tick-borne infections differed across the grazing systems and zones. The highest serum antibody prevalence (>60%) was recorded in the lowland zone under the free range and tethering grazing systems. The lowest tick challenge and serum antibody levels (<50%) were recorded in the midland and upland zones under a zero-grazing system. These findings suggest that endemic stability to East Coast Fever, babesiosis and anaplasmosis is most likely to have existed in the lowland zone, particularly, under the tethering and free-range grazing systems. Also, endemic stability for babesiosis existed in the upland zones. Endemic instability for East Coast Fever existed in the midland and upland zones. These structured observational studies are instrumental in planning of control strategies for ticks and tick borne diseases since production systems and the cattle population at high risk of the diseases in the district have been identified. Abbreviation: / zone: agro-ecological zon

Maternal Malaria and Malnutrition (M3) initiative, a pooled birth cohort of 13 pregnancy studies in Africa and the Western Pacific.

PURPOSE: The Maternal Malaria and Malnutrition (M3) initiative has pooled together 13 studies with the hope of improving understanding of malaria-nutrition interactions during pregnancy and to foster collaboration between nutritionists and malariologists. PARTICIPANTS: Data were pooled on 14 635 singleton, live birth pregnancies from women who had participated in 1 of 13 pregnancy studies. The 13 studies cover 8 countries in Africa and Papua New Guinea in the Western Pacific conducted from 1996 to 2015. FINDINGS TO DATE: Data are available at the time of antenatal enrolment of women into their respective parent study and at delivery. The data set comprises essential data such as malaria infection status, anthropometric assessments of maternal nutritional status, presence of anaemia and birth weight, as well as additional variables such gestational age at delivery for a subset of women. Participating studies are described in detail with regard to setting and primary outcome measures, and summarised data are available from each contributing cohort. FUTURE PLANS: This pooled birth cohort is the largest pregnancy data set to date to permit a more definite evaluation of the impact of plausible interactions between poor nutritional status and malaria infection in pregnant women on fetal growth and gestational length. Given the current comparative lack of large pregnancy cohorts in malaria-endemic settings, compilation of suitable pregnancy cohorts is likely to provide adequate statistical power to assess malaria-nutrition interactions, and could point towards settings where such interactions are most relevant. The M3 cohort may thus help to identify pregnant women at high risk of adverse outcomes who may benefit from tailored intensive antenatal care including nutritional supplements and alternative or intensified malaria prevention regimens, and the settings in which these interventions would be most effective

Some Factors Affecting the Sustainability of Tick and Tick-Borne Disease Control in Uganda. 1. Malpractice Associated with Acaricide Use

No Abstrac

Factors affecting the sustainability of tick-borne disease control in Uganda and malpractice Associated with acaricide use

No Abstract

Effects of anti-tick vaccines, recombinant serine protease inhibitors (RAS-1-2) and RIM 36 antigens against Rhipicephalus appendiculatus ticks’ feeding on Zebu cattle in Uganda

A preliminary trial of a cocktail of recombinant RAS-1-2 and RIM 36 antigens was conducted in Uganda to assess the effects of ant-tick vaccines against Rhipicephalus appendiculatus tick feeding on Zebu cattle under both experimental and natural conditions. Under experimental conditions, over a period of 28 days, the vaccinated group (n = 5) registered a mean female tick engorgement weight of 147.7 ± 41.8, mean tick egg weight of 90.5 ± 37.9, mean egg hatchability rate of 87.0 ± 12.1 and mean days ticks took to drop off of 6.4 ± 0.4 as opposed to the unvaccinated group (n =5) that had a mean female tick engorgement weight of 175.4 ± 63.0, mean tick egg weight of 99.7 ± 39.4, mean egg hatchability rate of 100 ± 9.6 and mean days ticks took to drop off of 6.4 ± 0.4. Upon exposure to natural tick challenge over a period of 61 days, there was no difference in total tick counts between the vaccinated group (mean tick count= 2-9) and non-vaccinated group (Mean tick count = 2-9) for the first 38 days. However, thereafter over a period of 23 days, tick counts for the vaccinated group (mean tick count = 3) were consistently much lower than those of the non-vaccinated group (mean tick count = 6) on exposure to natural tick challenge. In conclusion, the study revealed that a cocktail of recombinant RAS-1-2 and RIM 36 antigens had effect against tick feeding on Zebu cattle under both experimental and natural conditions with an efficacy rate of 65 % against R. appendiculatus under experimental conditions.Key words: Anti-tick vaccines; RAS-1-2; RIM 36; R. appendiculatus; Zebu cattle; Ugand

The impact of tick control on the productivity of indigenous cattle under ranch conditions in Uganda

The impact of tick control on the productivity of indigenous cattle was investigated in three herds of East African shorthorn Zebu and Zebu×Ankole (Nganda) breeds, maintained under three tick management systems practised under ranch conditions: twice-a-week dipping, once-a-month dipping, and no tick control. The milk production and the growth rates of pre-weaned and post-weaned calves were monitored once a month over a period of 34 months. Milk offtake was 23% higher during the heavy rainy seasons than in the long dry seasons. Twice-a-week dipping increased the milk offtake by 21% in the second year of study and prolonged the duration of lactation in cows. Similarly, twice-a-week dipping increased the pre-weaning growth rate by 39% in the second year of study, but had no significant effect on the post-weaning growth rate. Generally, the growth rate of calves were greatest during the heavy rainy seasons and least during the long dry seasons. These results provide a basis for assessing the losses under different tick management systems in the various production systems

The effects of host resistance on the pick-up rates of ticks under natural infestation in Uganda

The pick-up rates of tick species by various resistant groups of animals, dipped once a month and not dipped were investigated under ranch conditions in Nabiswera, Luwero district, Uganda. During the first three weeks of exposure of cattle to natural tick infestation, two phases of tick build-up and one phase of decline in tick population were demonstrated with R. appendiculatus. The other tick species were too few for comparisons to be made. Each of these phases lasted about 7 days, except on animals dipped once a month where the phase of decline in tick population lasted only 3 days. These fluctuations in pick-up rates were attributed to differences between drop-off rhythms of engorged female ticks and reinfestation pressure of unfed ticks. The peak numbers of R. appendiculatus were determined by the carrying capacity of the ears of animals. After three weeks of exposure, the population of R. appendiculatus on cattle stabilized and this could be due to the attainment of an equilibrium balance between drop-off rhythms and reinfestations. The pick-up rates were highest on the low resistance (LR) groups of animals, followed by the medium resistance (MR) and was lowest on the high resistance groups (HR). These patterns of tick infestation were identical in both treatment groups of animals. The significance of using pick-up rates of ticks for differentiating the levels of host resistance in cattle are discussed

Maternal Malaria and Malnutrition (M3) initiative, a pooled birth cohort of 13 pregnancy studies in Africa and the Western Pacific.

PurposeThe Maternal Malaria and Malnutrition (M3) initiative has pooled together 13 studies with the hope of improving understanding of malaria-nutrition interactions during pregnancy and to foster collaboration between nutritionists and malariologists.ParticipantsData were pooled on 14 635 singleton, live birth pregnancies from women who had participated in 1 of 13 pregnancy studies. The 13 studies cover 8 countries in Africa and Papua New Guinea in the Western Pacific conducted from 1996 to 2015.Findings to dateData are available at the time of antenatal enrolment of women into their respective parent study and at delivery. The data set comprises essential data such as malaria infection status, anthropometric assessments of maternal nutritional status, presence of anaemia and birth weight, as well as additional variables such gestational age at delivery for a subset of women. Participating studies are described in detail with regard to setting and primary outcome measures, and summarised data are available from each contributing cohort.Future plansThis pooled birth cohort is the largest pregnancy data set to date to permit a more definite evaluation of the impact of plausible interactions between poor nutritional status and malaria infection in pregnant women on fetal growth and gestational length. Given the current comparative lack of large pregnancy cohorts in malaria-endemic settings, compilation of suitable pregnancy cohorts is likely to provide adequate statistical power to assess malaria-nutrition interactions, and could point towards settings where such interactions are most relevant. The M3 cohort may thus help to identify pregnant women at high risk of adverse outcomes who may benefit from tailored intensive antenatal care including nutritional supplements and alternative or intensified malaria prevention regimens, and the settings in which these interventions would be most effective