Nowadays, Ethiopia is experiencing rapid growth in its poultry sector. This is being driven by rising incomes and expanding middleclass, together with the fact that poultry products are among the cheapest sources of protein, and also due to increasing population of the country with an increasing demand for the supply of food. In the second Growth and Transformation Plan (2008-2012 E.C.), the country gave great priority for livestock sector production including poultry.
During this period, it is made clear that the traditional backyard family poultry production system that relies on indigenous scavenging chickens should be transformed to a market-oriented improved family poultry system with semi-scavenging crossbred chickens. The crossbred chickens are known to have far higher genetic potential for both eggs and meat, when combined with supplemental feeding and adequate health services.
As well, the number and size of specialized commercial scale broiler and layer have substantially increased (Livestock Master Plan, 2014). Despite the fact that poultry industry is growing fast in Ethiopia, the industry is facing many constraints from which infectious diseases are the predominant one, with a significant negative impact on its development.
Most infectious diseases of poultry are endemic in the country but some are emerging and re-emerging diseases. Generally, poultry diseases are responsible for a number of adverse economic impacts due to mortality and morbidity of chickens, cost of medication, miscarriage in production and international trade ban and public health significance.
Over the last couple of years, private poultry farm owners have reported the occurrence of newly emerging of disease outbreaks such as NVI. To prevent the loss of birds from such disease outbreaks, at least four big poultry farm owners operating in Ethiopia, are importing live and inactivated vaccine from abroad. Recently, various studies have already been conducted by NVI researchers in collaboration with different large scale commercial poultry farms and poultry multiplication centers with the aim of identifying major poultry diseases encountered in the sector.
The preliminary result based on clinical observation and postmortem examination of diseased chicken showed the introduction of new diseases into the country like Infectious Bronchitis, Egg Drop Syndrome, Marek’s disease, Avian Mycoplasmosis, Infectious bursal disease, fowl cholera and others. Laboratory confirmations have been done by NVI for certain pathogens like Marek’s Disease virus, Mycoplasma gallisepticum, Infectious bursal disease virus, Pasteurella multocida and other pathogens. Currently, these emerging and re-emerging diseases are widely distributed in all regions of the country and are creating serious problem to the sector and hence becoming a bottle neck for the success of the poultry development program incorporated in GTP II.
There is a lot of evidence that highlights the gravity of the problem which we have published so far on the identification and molecular characterization of poultry pathogens and many more are in the pipeline. Fowl cholera is a contagious bacterial disease of domesticated and wild avian species caused by infection with Pasteurella multocida.
It typically occurs as a fulminating disease with massive bacteraemia and high morbidity and mortality in older birds. It is widely distributed throughout the country. Infectious bursal disease (IBD) on the other hand which was first reported in Ethiopia in 2002 at privately owned commercial poultry farm is currently becoming among the most important disease for the juvenile poultry industry in the country. IBD and fowl cholera are the diseases that we can at least control by producing noble vaccine with our added experiences we have. Hence, we initiated this research project to address the existing serious problem posed on poultry production. This research project is not for scientific curiosity but to alleviate the big challenge that the poultry industry is facing in this county due to the two serious diseases mentioned above.
Ethiopian poultry production has a long traditional practice which is characterized by low input and low output. Attempts are underway to enhance chicken productivity and their contribution via importing exotic chickens, crossbreeding and distributing improved breeds to poor farmers living in the different part of the country Poultry mortalities caused by disease are estimated to range from 20% to 50% but they can rise as high as 80% during epidemics in Ethiopia.
Diseases are also considered to be the most important factors responsible in reducing both the number and productivity of chickens (Aberra and Tegegne, 2007). Among the impediments of the poultry development in this country constitute diseases like infectious bursal disease and fowl cholera with frequent outbreaks and presenting a serious threat and challenge to the young growing poultry industry in Ethiopia (Mazengia, 2012). In Ethiopia, despite the frequent complaints of the state and private poultry farms to the National Veterinary Institute due to the high morbidity, mortality, loss of production and high treatment cost associated with fowl cholera, the prevalence of the disease has not yet been quantified.
According to Ethiopian animal health yearbook 2011, from the passive surveillance disease report, a total of 6 outbreaks with 336 cases and 72 deaths, with total birds’ population at risk stand at 108,775. However, the figures are not supported by laboratory confirmation but are merely based on clinical features and on owners’ information (Ethiopia Animal Health Yearbook, 2011). Although there is vaccine against fowl cholera produced elsewhere, poultry enterprises in Ethiopia are still experiencing problems with this disease due to unavailability of the vaccine in the local market.
To this end, there has been a strong endeavor to manufacture the vaccine at the National Veterinary Institute. There was research done at National veterinary institute by Bitew et al. 2009 on the development and efficacy trial of inactivated fowl cholera vaccine using local isolates and found that the vaccine is very effective in conferring prevention against the disease in experimentally challenged layer chickens. This is the only report which needs to be further validated by other researchers with subsequent development of standard operating procedures (SOP) for its industrial production.
The other diseases presenting serious challenge to poultry farming is IBD which was first reported in Ethiopia in 2002 at privately owned commercial poultry farm. Subsequently, it is becoming among the most important disease for the juvenile poultry industry in the country. The disease is caused by infectious bursal disease virus (IBDV). It is dsRNA virus with bi-segmented genome. The larger segment A encodes four viral proteins designated as VP2, VP3, VP4 and VP5. The smaller segment B encodes only VP1 which has polymerase activity. Vaccination is the principal method to control IBD. Control of IBD has been complicated by the recognition of variant and very virulent strains within serotype 1 (Rasool and Hussain, 2006). Research findings and case reports coming from various regions of the country indicated that episodes of IBD outbreaks in several commercial poultry farms, poultry breeding and multiplication centers have wiped out large number of exotic chickens despite regular vaccination practices and improved bio security measures. Over the past few years, 25 to 75% of the deaths/losses in exotic and cross chickens have been associated with infectious bursal disease. Even in the recent sero surveillance study, it has been found up to 90% positive.
NVI is producing IBD vaccine since 2010 by utilizing specific pathogen free (SPF) embryonated chicken fibroblast cells. However, maintaining the huge amount of chicken embryonated eggs for large scale production of the vaccine is very difficult and not economically feasible due to our dependence on imported SPF which rely on the limited hard currency.
Moreover, during incubation of embryo production, the fertility rate is low ending up much of the eggs unusable. This led the production of IBD vaccine costly and needed another cost effective option to our urgent need. There are reports of adapting IBD virus on vero cells in different countries like Bangladesh and in Pakistan. Due to greater suitability of in vitro growth, short generation time, availability, persistent cellular properties, easiness to handle and maintenance, vero cells are used to cultivate, adapt and attenuate different viruses.
There are also some trials to produce attenuated vvIBDV vaccine. However, production of Vero cell adapted IBD vaccine has never been tried in Ethiopia which could be a useful alternative for maximal production of the vaccine. To conclude, this research project is aimed at addressing the need for a very urgent and timely action in reducing the impact of these devastating diseases which are presenting great challenges to both the rural poor and the commercial poultry industry.
Herald March 15/2019
BY DAGNE BIAZEN
