Cattle ticks and tick-borne diseases: a review of Uganda's situation.

Herein we review the epidemiology of ticks and tick-borne diseases (TTBDs), their impact on livestock health and on the economy, control and associated challenges in Uganda. Ticks are leading vectors of economically important pathogens and are widespread in Uganda due to suitable climatic conditions. Besides the physical injury inflicted on the animal host, ticks transmit a number of pathogens that can cause morbidity and mortality of livestock if untreated, resulting in economic losses. Uganda suffers an aggregated annual loss (direct and indirect) of over USD 1.1 billion in the TTBDs complex. East Coast fever (ECF) caused by a protozoan haemoparasite, Theileria parva, is the most prevalent and economically important tick-borne disease (TBD) in Uganda and its vector, the brown ear tick (Rhipicephalus appendiculatus) widely distributed. Other prevalent TBDs in Uganda include anaplasmosis, babesiosis and heartwater. We highlight the role of agro-ecological zones (AEZs) and livestock management system in the distribution of TTBDs, citing warm and humid lowlands as being ideal habitats for ticks and endemic for TBDs. Control of TTBDs is a matter of great importance as far as animal health is concerned in Uganda. Indigenous cattle, which make up over 90% of the national herd are known to be more tolerant to TTBDs and most farms rely on endemic stability to TBDs for control. However, exotic cattle breeds are more capital intensive than indigenous breeds, but the increasing adoption of tick-susceptible exotic cattle breeds (especially dairy) in western and central Uganda demands intensive use of acaricides for tick control and prevention of TBDs. Such acaricide pressure has unfortunately led to selection of acaricide-resistant tick populations and the consequent acaricide resistance observed in the field. Vaccination against ECF, selective breeding for tick resistance and integrated tick control approaches that limit tick exposure, could be adopted to interrupt spread of acaricide resistance. We recommend increasing monitoring and surveillance for TTBDs and for emerging acaricide resistance, improved extension services and sensitization of farmers on tick control measures, appropriate acaricide use and the development and implementation of vaccines for the control of TTBDs as more sustainable and effective interventions. A tick control policy should be developed, taking into account variations of agro-ecological zones, farm circumstances and indigenous technical knowledge, and this should be incorporated into the overall animal health program.

Kasaija PD ，Estrada-Peña A ，Contreras M ，Kirunda H ，de la Fuente J ... -  《-》

Prevalence of tick-transmitted pathogens in cattle reveals that Theileria parva, Babesia bigemina and Anaplasma marginale are endemic in Burundi.

Nyabongo L ，Kanduma EG ，Bishop RP ，Machuka E ，Njeri A ，Bimenyimana AV ，Nkundwanayo C ，Odongo DO ，Pelle R ... -  《Parasites & Vectors》

Molecular epidemiology of Babesia species, Theileria parva, and Anaplasma marginale infecting cattle and the tick control malpractices in Central and Eastern Uganda.

East Coast fever, babesiosis, and anaplasmosis are the major tick-borne diseases affecting cattle productivity in Uganda. The emergence of acaricide-resistant ticks is suspected to have caused a rise in hemoparasites. This study sought to detect and characterize hemoparasites among farms in acaricide-failure hotspots of central as compared to the acaricide-failure naïve areas in Eastern Uganda. Nested PCR assays were performed to determine the prevalences of Babesia bovis, Babesia bigemina, Theileria parva, and Anaplasma marginale in cattle blood samples sourced from randomly selected farms. Randomly selected isolates were sequenced to determine the genetic diversity of the parasites using the following marker genes: B. bovis spherical body protein 4, B. bigemina rhoptry-associated protein 1a, T. parva 104 kDa microneme-rhoptry antigen, and A. marginale major surface protein 5. Furthermore, partially and fully engorged adult ticks were collected for taxonomy, and tick-control practices were assessed using a semi-structured questionnaire. The prevalences of B. bigemina, T. parva, and A. marginale in cattle were 17.2, 65.1, and 22.0%, and 10.0, 26.5, and 3% in the central and eastern region, respectively. Whilst, B. bovis was not detected in the farms involved. The sequences for B. bigemina, T. parva, and A. marginale from the central region showed 99% identity with those from the eastern region. Of the 548 ticks collected, 319, 147, 76, and 6 were Rhipicephalus (Boophilus) decoloratus, Rhipicephalus appendiculatus, Amblyomma variegatum, and Rhipicephalus evertsi evertsi, respectively. The Rhipicephalus ticks were more abundant in the central region, whereas A. variegatum ticks were more abundant in the eastern region. Tick control malpractices were found in both Central and Eastern Uganda, and 42 of the 56 surveyed farms lacked appropriate restraining facilities and so they utilized either ropes or a 'boma' (enclosure). In summary, B. bigemina, T. parva, A. marginale and their co-infections were more prevalent in the central than eastern region; even though, tick control malpractices were observed in both regions. Therefore, an urgent tick and TBD control strategy is needed.

Tayebwa DS ，Vudriko P ，Tuvshintulga B ，Guswanto A ，Nugraha AB ，Gantuya S ，Batiha GE ，Musinguzi SP ，Komugisha M ，Bbira JS ，Okwee-Acai J ，Tweyongyere R ，Wampande EM ，Byaruhanga J ，Adjou Moumouni PF ，Sivakumar T ，Yokoyama N ，Igarashi I ... -  《-》

Prevalence and spatial distribution of Theileria parva in cattle under crop-livestock farming systems in Tororo District, Eastern Uganda.

Muhanguzi D ，Picozzi K ，Hatendorf J ，Thrusfield M ，Welburn SC ，Kabasa JD ，Waiswa C ... -  《Parasites & Vectors》

Economic impact of predominant ticks and tick-borne diseases on Indian dairy production systems.

As per 20th livestock census, India possessing 193.46 million cattle and 109.85 million buffaloes in organized and unorganized sectors. These animals are suffering from tick infestation almost throughout the year causing both direct and indirect losses. Repeated use of chemical acaricides for tick management resulted in the establishment of acaricide resistant tick populations, insecticide residues in livestock products and environmental pollution. In the present study, analysis of the data generated during 1990-2021 revealed pooled prevalence of infestations in cattle and buffaloes was 53% [95% CI = 47-60%] and 38% [95% CI = 28-49%], respectively. Based on peripheral blood smear examination the prevalence of theileriosis, babesiosis and anaplasmosis in cattle is estimated as 17% [95% CI = 12-24%], 4% [95% CI = 3-6%] and 5% [95% CI = 3-7%], respectively, while in buffalo the prevalence of infection is estimated as 7% [95% CI = 2-21%], 2% [95% CI = 0-5%] and 8% [95% CI = 2-36%],respectively.To estimate economic impact, both direct (reduction in milk production, cost of treatment, leather depreciation) and indirect (milk loss and treatment cost) losses were taken into consideration. Loss of milk production was predicted as 13.91, 56.91 and 85.34L/cross-bred cow/lactation in low, moderate and high tick infestation conditions, respectively. Whereas, 20.10, 7.01L milk/buffalo/lactation in Hyalomma spp. and Rhipicephalus spp. infestation was estimated. Similarly,the estimated loss of milk production due to clinical theileriosis, babesiosis and anaplasmosis was 57.96, 30.96 and 59.22L, respectively. The cumulative (milk loss, treatment cost and leather loss) loss due to tick infestation was calculated as 46199.31 million INR (USD595.07 million) while due to TBDs 14877.15 million INR (USD191.15 million) = 61076.46 million INR (USD787.63 million). The data provided base line information for the policy maker to develop strategies at government level so that the significantly high cumulative loss of 787.63 million USD due to ticks and tick borne diseases (TTBDs) can be minimized.

Singh K ，Kumar S ，Sharma AK ，Jacob SS ，RamVerma M ，Singh NK ，Shakya M ，Sankar M ，Ghosh S ... -  《-》