Systematic Review Methodology to Identify, Quantify and Describe Livestock Zoonoses Based on Scientific Publications

Abstract

About 60% of human infectious diseases are zoonotic. To date, there have been several approaches to create an inventory of human zoonotic diseases but information is lacking regarding zoonotic diseases that affect specific livestock species in regions where diseases are most likely to emerge. Most zoonoses are under-reported both by the veterinary services (because many of them do not cause important losses to livestock or have no trade implications) and by the public health services (because of their historically rare occurrence). There are multiple data sources on zoonoses (official reporting, media, scientific publications and prioritization exercises at national level), all of them subjected to strong biases. Only a combination of all those sources will give an accurate picture of the situation. In this study we developed an objective methodology that allows the relative quantification of the occurrence of zoonoses and the livestock species affected per region by recording the number of publications on each pathogen in the PubMED database as a measure of importance. We performed the search in five priority regions for the emergence of disease. Influenza was the most predominant cited disease in the articles retrieved from three areas in the globe. The latter reflects the importance and magnitude of the H5N1 and H1N1 epidemics in those regions. The methodology created in this study provides several benefits: it assess the impact and prioritize livestock-zoonotic diseases that need intervention and it provides a scientifically grounded estimation of the state of livestock-zoonotic diseases (sometimes neglected by the official reports and the media) which will help to better design surveillance and intervention strategies of zoonotic pathogens on livestock.