Date of Award

January 2016

Document Type

Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Albert I. Ko

Abstract

Background

Brucellosis and Q fever may impart high morbidity in humans and economic losses among livestock. Yet, a systematic investigation has not been performed in Thailand, where a significant proportion of the rural population may be vulnerable to these zoonotic diseases.

Objectives

We surveyed the seroprevalence of brucellosis and Q fever in livestock from Thai communities at the border with Cambodia, evaluated risk factors for seropositivity, and performed a risk assessment for potential transmission to farmers.

Methods

We selected herds of beef and dairy cattle and small ruminants (sheep and goats) for Sa Kaeo province in 2015 using a two-stage random sampling design. Rose Bengal, ELISA and complement fixation assays were performed to evaluate brucellosis seroprevalence, while ELISA was performed to evaluate Q fever seroprevalence. We interviewed farmers to evaluate potential risk factors for transmission among herds and to the community.

Results

We surveyed a total of 520 individuals from 143 farms (15 small ruminant flocks, 117 beef cattle herds and 11 dairy cattle herds). Brucellosis seroprevalence in beef cattle and small ruminants was respectively 2.6% (0.7-7.9) and 13.3% (2.3-41.6). Q fever seroprevalence in beef cattle, dairy cattle and small ruminants was respectively 4.3% (1.6-10.2), 27.3% (7.3-60.7) and 33.33% (13.0-61.3). We found no significant association between known risk factors for herd-transmission and seropositivity of the farms. Lack of disinfectant use (64.3%-90.9%) and consumption of placenta by farmers (40%-80.8%) were frequent among farms.

Discussion

This study identified a significant burden associated with brucellosis and Q fever among livestock and a potential risk for spillover transmission to farmers via consumption of placenta and lack of disinfectant use. Efforts should therefore be made to implement routine surveillance and prevention of brucellosis and Q fever in livestock and evaluate the potential burden of these zoonotic diseases among subsistence farming populations in the region.

Comments

This thesis is restricted to Yale network users only. It will be made publicly available on 05/06/2018

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