The potential role of an inactivated thermostable vaccine in the control of Newcastle disease in traditionally free-roaming poultry in Central and West Africa

Abstract

In spite of the clinical and economic importance of Newcastle disease (ND), vaccination of traditional poultry flocks is not a common practice in Cameroon and other countries in West and Central Africa. This study was designed to demonstrate the importance of vaccination against ND and to propose a sustainable vaccination programme with a LaSota strain of NDV vaccine (Multivax) produced in Cameroon. It consisted of field vaccination trials, determination of a strategic vaccination programme through sero-monitoring and assessing vaccine keeping quality under field conditions. Twelve months monitoring of vaccinated flocks revealed that the epidemic periods of March-April and December-January passed without major incidence in flocks. Mortalities were reduced from above 90% in previous years to 10.8% and 24.6% in two experimental sites respectively. Vaccination antibodies were sustained above protection threshold for about 80 days. A booster administered 35 days after the priming dose did not have any effect on declining serum antibodies. The vaccine remained efficacious in eliciting antibody production for up to 10 weeks after initial use and kept at ambient temperature averaging 34 degrees C. For good protection in a less intense vaccination programme, it would be necessary to administer the vaccine one month to the anticipated month of epidemic, thus requiring at least two campaigns per year.

Thermostable Vaccines in Veterinary Medicine: State of the Art and Opportunities to Be Seized

“…Most of the studies included are on vaccines against avian diseases, and, in particular, against NDV [42][43][44][45][46][52][53][54][55][56][57][58]67,[69][70][71]73,75,76,78,79,[82][83][84]. Developing a thermostable vaccine for Newcastle disease (ND) was considered a priority for non-governmental organisations (NGOs) and studies were funded to evaluate the effectiveness and economic viabilities of the vaccination in developing countries.…”

Livestock pathology in the central African region: some epidemiological considerations and control strategies

“…Avian pathology as a constraint to poultry production is not a peculiarity of this region but a continent-wide problem. ND features as the most important health problem (Mopaté and Idriss, 2001;Alabi and Isah, 2002;Maho et al, 2004;Awa et al, 2004Awa et al, , 2008bMopaté and Maho, 2005) particularly in traditional poultry where vaccination is not routinely done. In the semi-arid and arid regions of Cameroon and Chad, two epidemic periods have been noted: the first peak during the intense heat of March and April and the second in the cold dry months of December and January, causing mortality that varies from 70 to 100% (Awa and Ngo Tama, 1997;Maho et al, 2004;Mopaté and Maho, 2005;Awa et al, 2008a, b).…”

“…ND features as the most important health problem (Mopaté and Idriss, 2001; Alabi and Isah, 2002; Maho et al , 2004; Awa et al , 2004, 2008b; Mopaté and Maho, 2005) particularly in traditional poultry where vaccination is not routinely done. In the semi-arid and arid regions of Cameroon and Chad, two epidemic periods have been noted: the first peak during the intense heat of March and April and the second in the cold dry months of December and January, causing mortality that varies from 70 to 100% (Awa and Ngo Tama, 1997; Maho et al , 2004; Mopaté and Maho, 2005; Awa et al , 2008a, b). The role of Gumboro disease in traditional poultry at present seems to be ill-defined but its importance in intensive production units has been underscored (Alabi and Isah, 2002).…”

“…The major constraint associated with this is the inappropriateness of the intensive vaccination programmes practiced in intensive commercial poultry farms which often involve the use of vaccines that need to be maintained in a cold chain. Having identified high risk epidemic periods in the Savannah region of central Africa, 2 to 3 vaccination campaigns per year are proposed (Awa et al , 2008a, b; Maho et al , 2009) to pre-empt outbreaks of ND in the cold dry period of December–January and the hot humid period of April–June. Field application of the programme using either an inactivated thermo-tolerant injectable vaccine produced by the Cameroon National Veterinary Laboratory or an imported live vaccine administered intra-occularly or in the drinking water in selected sites in Cameroon, Chad and the CAR led to reductions of mortality from over 90% to less than 20% in most cases during epidemic periods.…”

“…Direct losses through infections and indirect losses arising from the unsuitability of tsetse-infested areas to livestock rearing in sub-Saharan Africa were estimated at US$5 million per year (ILRAD, 1994). Pathologies of similar economic importance include dermatophilosis and foot-and-mouth disease in cattle (Achukwi and Saliki, 1990; Awa et al , 2004, 2008a, b; Sow et al , 2005) peste des petits ruminants and gastrointestinal helminthosis (Ndamukong et al , 1989; Awa et al , 2002; Njoya et al , 2005a) and Newcastle disease (ND) in poultry (Maho et al , 2004; Mopaté and Maho, 2005; Awa et al , 2008a, b).…”