Evaluating the risk of spread of H5N1 highly pathogenic avian influenza in Kenya

Outbreaks of H5N1 highly pathogenic avian influenza (HPAI) occurred in 11 countries in Africa between the years 2006 – 2008. Kenya did not get exposed to the disease but as the perceived risk of introduction of the HPAI virus heightened, the demand for poultry and poultry products waned. This resulted in enormous economy-wide impacts. To generate information that could be used for improving the contingency plans that had been developed by the Department of Veterinary Services, we assessed the risk of spread of the disease in the country using a spatial simulation model; the model used data on topography, landscape features, and vegetation and road networks in a spatial lattice of 1 square km. In parallel, we constructed risk maps for the introduction and the spread of HPAI. The results of the simulation model and the risk maps agree that the areas of Nairobi, Mombasa and Nyanza show the highest risk for the spread of the disease. We also conducted a qualitative risk assessment study involving small scale commercial (sector 3) and backyard (sector 4) poultry farms to identify poultry production practices that could be associated with the release or exposure of the virus at the farm-level. The model identified the ports of Mombasa and the JKIA as potential gateways of introduction of the disease. It also revealed that densely populated areas, e.g. cities, had higher risk of experiencing outbreaks compared to sparsely populated ones. Similarly, areas that have dense road networks had higher risk of experiencing outbreaks. Qualitative risk assessment studies indicated that the risk of transmission of the disease from an infected backyard farm was higher than that from an infected small scale commercial farm due to poor biosecurity practices practised in such farms. Free-range production systems in backyard poultry farms, for example, allow unlimited contact between poultry and “farm-bridge” animals and birds. All these studies identified geographical zones and farm practices that should be targeted for surveillance. They also identified areas for further research

Effect of Deposition Parameters on Optical and Electrical Properties of SnO2: Al Thin Films Prepared by Spray Pyrolysis Technique for Optoelectronic Devices

Transparent Aluminum doped tin oxide (SnO2:Al) thin films with different Al percentage (1.96%, 3.85%, 5.66%, 7.41% and 9.09%) were fabricated using a low cost spray pyrolysis technique at optimized deposition parameters. Substrate temperature, carrier gas pressure and spray outlet to substrate distance were varied to obtain optimum conditions for deposition. Optical characterization of the deposited films was carried out to the average transmittance, optical constants (refractive index (n) and extinction coefficient (k)) and the band gap. The calculated refractive indexes of the films with various Al concentrations were in the range of 1.469 Al at. % to 1.914 Al at. % w with 5.37% at. % being the optimum, while the average transmittance was between 70% and 80% and band gap of 3.96 eV. The calculated resistivity was in the order of 10-4 Ωcm

Alignment of poultry sector actors with avian influenza control in Kenya

Kenya has a high risk of being infected with highly pathogenic avian influenza (HPAI) because it (i) lies along the migratory bird routes, (ii) engages in formal and informal cross-border trade in live birds and other poultry products, (iii) lacks capacity to regulate the poultry industry trade and (iv) is well connected to the region and with the rest of the world through its air and road transport networks. The government developed a contingency plan for prevention and control of the disease in 2005 which describes a set of mitigation measures that could be implemented at various stages of the outbreak. The contingency plan identifies national and international agencies as well poultry value chain actors as being key players that would either deliver or implement HPAI control measures. It has not been established, however, whether these players would comply appropriately to ensure the successful implementation of the HPAI control measures. This is because actor willingness to comply depends fundamentally on the alignment of control measures with actor capacity to comply, their current practices, and incentives they face. This study (i) characterised control measures in terms of expected degree of compliance by actors in the poultry value chain and the agents responsible for implementing the measures, and (ii) identified actors who may be expected to prove to be compliance fail-points to successful implementation of control measures. Four HPAI control measures were studied: these are biosecurity, reporting, movement control, and culling and compensation

Qualitative release and exposure assessment on the risk of HPAI transmission between sector 4 farms and between sector 3 and sector 4 farms in Kenya

This study assessed the risk of transmission of highly pathogenic avian influenza (HPAI) between backyard poultry (S4) farms and between S4 and semi-commercial (S3) farms in Kenya. It was designed to complement findings of a study that had been conducted in 2007 by the DVS and FAO to evaluate the risk of introduction of the disease into the country. It followed the OIE risk analysis framework where release, exposure and consequence assessments are done successively and their risk parameter estimates combined to obtain an overall risk estimate for a given pathway. Risk questions were formulated in a stakeholder workshop that was convened at ILRI in Nairobi on 2-3 October 2008. A total of nine risk pathways were formulated (4 for the first question, 3 for the second and 2 for the third as indicated by the roman numerals above). Risk parameters were estimated using qualitative methods because data needed for quantitative analyses were not available. Data and information used in the analysis were obtained from an expert elicitation survey, project reports or published literature. The expert elicitation survey used structured questionnaires. For each question raised, respondents were expected to give the most likely answer, its minimum and maximum value, the level of confidence on the answer given (in a scale of 1 to 5 with 1= not confident, 5= very confident) and the source of the information used for reference. Risk estimates were determined as very high, high, medium, low, very low or negligible. Overall risk estimates for each pathway were obtained by combining estimates for each step of the pathway using a combination matrix described by Zepeda (1998). The level of uncertainty for each risk parameter estimate was described as low, medium or high