A retrospective analysis of the epidemiology and control measures of contagious bovine pleuropneumonia in the northern communal areas of Namibia from 2001 to 2013

Abstract

Contagious bovine pleuropneumonia (CBPP) caused by Mycoplasma mycoides subspecies mycoides (small colony) is an insidious pneumonic disease of cattle and poses a challenge to cattle production in sub-Saharan Africa. It is transmitted by direct contact and can manifest as peracute, acute or chronic disease. It has been described as one of the trans-boundary animal diseases of cattle known to pose trade barriers throughout many countries in Africa (Jores et al., 2013). This study describes the occurrence of CBPP in the northern communal areas (NCA) of Namibia from 2001 to 2013. All the data was collected from annual reports at the epidemiology section of the Division of Veterinary Services. The annual reports captured all outbreak foci together with their GPS coordinates and this facilitated the analysis of temporal and spatial occurrence of the disease. The suspected cases that were not confirmed at the laboratory but had clinical manifestation typical of CBPP were also recorded. A total of 70 outbreaks were recorded from 2001 to 2013. The highest number of outbreaks was recorded in 2005 with 11 laboratory confirmed outbreaks. Zambezi and Kunene North regions were the most affected. From 2002 to 2004, six outbreaks were recorded for each year and in 2006 eight outbreaks were reported. It's important to note that from 2007 up to 2012; isolated outbreaks with less than five laboratory confirmed cases were recorded. Measures of risk including incidence and mortality rates, as well as vaccination coverage of the population at risk were calculated and described per year for each of the different regions in the NCA. CBPP is confined to the NCA especially in regions that share open border with Angola and Zambia. Zambezi, Oshikoto, Ohangwena, Omusati, Kunene and Kavango are the hot spots of CBPP in the NCA. Despite good vaccination coverage, outbreaks still occurred hence the disease cannot be eradicated with annual vaccinations alone. Other factors such as the open border between Namibia and Angola that facilitates free movement of animals between the two countries have to be addressed first.