Bovine petechial fever (Ondiri disease)

Area of Science:

• Veterinary Medicine
• Infectious Diseases
• Rickettsial Pathogens

Background:

• Bovine petechial fever is a Rickettsial disease diagnosed exclusively in Kenya, East Africa.
• The disease presents with widespread petechial and ecchymotic hemorrhages, potentially leading to high fatality rates in untreated cattle.
• The causal agent, Cytoecetes ondirii, is classified within the Ehrlichiae tribe and resides in leukocyte cytoplasm.

Purpose of the Study:

• To describe the clinical and etiological characteristics of bovine petechial fever.
• To highlight the potential geographic spread and economic impact of this Rickettsial disease in East Africa.
• To identify potential reservoir hosts and transmission vectors for Cytoecetes ondirii.

Main Methods:

• Demonstration of the causal organism, Cytoecetes ondirii, in polymorphonuclear granulocytes and other leukocytes from peripheral blood.
• Review of clinical signs, including widespread hemorrhages on mucosal and serosal surfaces.
• Investigation of potential reservoir hosts, including bushbuck and African buffalo, for infectivity duration.

Main Results:

• Cytoecetes ondirii, the causative agent, was identified within the cytoplasm of leukocytes.
• Infected bushbuck blood remained infective for at least 2 years, and African buffalo for at least 5 weeks.
• Evidence suggests transmission by an as-yet-unidentified arthropod vector.

Conclusions:

• Bovine petechial fever poses a significant threat to cattle in East Africa due to its high fatality rate and potential for widespread distribution.
• Bushbuck and African buffalo may act as amplifying and reservoir hosts, maintaining the infection in the region.
• Further research is needed to identify the arthropod vector responsible for transmitting Cytoecetes ondirii to prevent disease spread.