HEARTWATERAnother Potential Foreign Animal

Disease

Prepared by : Monoclonal Antibody Section,

Veterinary Research Institute (VRI)

• a.k.a COWDRIOSIS, is non-zoonotic disease but often acute, fatal, infectious and tick-borne (Amblyomma ticks) rickettsial on ruminants.

• caused by bacteria Ehrlichia ruminantium (Dumler, 2001).• widespread in most of Africa, also found on a few

Caribbean islands and threatening the American mainland. However, no case reported in Asia regions yet (OIE, 2010).

• can cause high mortality (up to 90%) in susceptible wild and domestic ruminants (cattle, sheep, goats, antelope and buffalo) esp. young animals and non-native breeds

INTRODUCTION

Goats and sheep are more susceptible than cattle, and European breeds are generally more susceptible than indigenous African breeds.

Amblyomma ticks

Goat Sheep Cattle

GEOGRAPHICAL DISTRIBUTION

According to OIE 2010, no case for this disease ever reported in Southest Asia (including Malaysia)

CLINICAL SIGNS• caused by an increased vascular permeability and consequent oedema and

hypovolaemia.• symptoms include neurological signs such as tremors and head pressing,

respiratory signs such as coughing and nasal discharge, and systemic signs such as fever and loss of appetite.

• high death rates in acute stage without many clinical manifestations while in the higher recovery rate in peracute stage.

• physical examination may reveal petechiae of the mucous membranes, tachycardia and muffled heart sounds.

EXTRA INFO:• can also cause reproductive and gastrointestinal disease.• recovered animals become carriers of infection • certain wild animals can play a role as reservoir

fever and loss of appetitecoughing and nasal dischargeoedema and hypovolaemiaa

DIAGNOSIS(POST-MORTEM EXAMINATION)

• Light yellow transudate within the thorax, pericardium and abdomen.

• Pulmonary oedema and mucosal congestion are regularly seen along with frothy fluid in the airways and cut surfaces of the lungs.

• Hydropericardium, hydrothorax and lung oedema are commonly associated post-mortem signs.

Histopathological identification of Ehrlichia ruminantium: by preparing the hippocampus under Giemsa staining or by Histopathology (brain/kidney).

stained Ehrlichia ruminantium

DIAGNOSTIC TECHNIQUES

(OIE Terrestrial Manual)1. Identification of the agent (Isolation of Ehrlichia ruminantium )

a) using in-vitro cultureb) using in-vivo culture

2. Molecular methods (detection of Ehrlichia ruminantium )a) using DNA probesb) using PCR and nested PCRc) using the reverse line blot techniqued) using real-time PCR

3. Serological tests a) IFAT with infected endothelial cell tissue culture as

antigen (CIFA test) b) MAP1-B enzyme-linked immunosorbent assay c) MAP1 competitive enzyme-linked immunosorbent

assay

Bacterial Isolation

Fluorecense Test

ELISA

TREATMENT AND CONTROLTREATMENT

• During the early stages, animals may be treated with sulfonamides and tetracyclines.

• In advanced disease, prognosis is poor.

CONTROL• Tetracyclines can also be used prophylactically when animals

are introduced into an area endemic with cowdriosis. • A live blood vaccine is available for protection of young stock,

but animals may require treatment for the disease post-vaccination.

• Ectoparasiticides dips such as Rhipicephalus (Boophilus) and Hyalomma species will contribute to control of vectors of Ehrlichia ruminantium.

REFERENCES1. Dumler JS, Barbet AF, Bekker CP, et al. (2001). "Reorganization of genera in the

families Rickettsiaceae and Anaplasmataceae in the order Rickettsiales: unification of some species of Ehrlichia with Anaplasma, Cowdria with Ehrlichia and Ehrlichia with Neorickettsia, descriptions of six new species combinations and designation of Ehrlichia equi and 'HGE agent' as subjective synonyms of Ehrlichia phagocytophila". Int. J. Syst. Evol. Microbiol. 51 (Pt 6): 2145–65. doi:10.1099/00207713-51-6-2145. PMID 11760958.

2. http://www.ebi.ac.uk/2can/genomes/bacteria/Ehrlichia_ruminantium.html3. "Heartwater". Animal and Plant Health Inspection Service. U.S. Department of

Agriculture. Retrieved 2008-04-13.4. C H A P T E R 2 . 1 . 6 . HEARTWATER. OIE Terrestrial Manual (2008).5. CFSPH Technical Fact Sheets. Heartwater at http://www.cfsph.iastate.edu/

DiseaseInfo/6. Heartwater: Another Potential Foreign Animal Disease. http://www.vetmed.

ucdavis.edu/vetext/INF-DA/INF-DA_HEARTWATER.HTML7. USDA APHIS factsheet. Heartwater. http://www.aphis.usda.gov/lpa/

pubs/fsheet_faq_notice/fs_ahheartw.html

Prepared by : Monoclonal Antibody Section,

Veterinary Research Institute (VRI)