The occurrence of selected disease syndromes of livestock detected through a passive surveillance system in western Kenya

Abstract

Animal disease surveillance has been integral in improving early warnings and predicting disease emergence and spread in humans as well as in animal hosts. Syndromic surveillance is an emerging approach to monitoring populations for change in disease levels, based on the distribution of clinical signs that occur in sick individuals. A number of disease syndromes in livestock may be associated with increased likelihood of endemic, emerging, re-emerging and zoonotic diseases. The overall aim of the current study was to implement a passive animal disease surveillance and response system with a capability of detecting emerging zoonotic diseases in domestic and peridomestic animals, in a trial site where active human disease surveillance is ongoing. The project was intended as a demonstration of the system on a short-term basis, with the intention of conducting an evaluation of its performance later. The specific objective was to evaluate and investigate four selected disease syndromes (abortions/stillbirths, sudden death, neurologic signs, red urine) affecting cattle, sheep and goats using a mobile phone-based rapid short message system (SMS) reporting system within the study site, to allow animal owners to report cases of animal disease. SMS reports were logged in a central database and generated a response from a veterinary team to investigate cases. The study was conducted in Asembo division of Rarieda Sub-county of Siaya County, Nyanza Province in western Kenya, from July 2011 through June 2012. A total of 185 events were reported during the study period. Of these, 46 (24.9%) were considered invalid on investigation. The 139 valid events comprised 75 cases of abortions, 43 cases of sudden death, 12 cases of red urine, and 9 cases of nervous signs. Goats were the most frequently affected species at 47% (n=64), cattle at 34% (n=47) and sheep at 19% (n=26). The incidence rate of events by species (per 1,000 population per year) was 7.3 in sheep, 6.5 in goats and 4.1 in cattle. The incidence rate of abortions by species per 1,000 population per year was 5.1 in sheep, 4.0 in goats and 1.5 in cattle. The incidence rate of sudden deaths by species per 1,000 population per year was 2.1 in goats, 2.0 in sheep and 1.3 in cattle. The incidence rate of neurological signs by species per 1,000 population per year was 0.6 in cattle, 0.3 in sheep and 0.2 in goats. The incidence rate of red urine by species per 1,000 population per year was 1.1 in cattle, 0.1 in goats and 0 in sheep. Presumptive diagnoses implicated haemoparasites infections; including theileriosis, babesiosis, anaplasmosis and heartwater and bacterial infections (septicaemia, clostridial infections and anthrax). This project demonstrated that passive animal surveillance using mobile technology is feasible in a resource-constrained setting, although it is likely that cases were underreported.