Impact assessment study of the Nigeria avian influenza control and human pandemic preparedness and response project

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Issues and strategies in ex-post evaluation of intervention against animal disease outbreaks and spread
(Journal Article, 2014-12) Fadiga, M.L.; Katjiuongua, Hikuepi B.
Animal disease outbreaks pose a significant threat in terms of potential economic losses, reduced productivity, and negative impacts on public health, food security and nutrition. This paper considers four issues in ex-post evaluation of animal disease interventions: firstly, a counterfactual involves simulating disease trajectories without the intervention. But some diseases can become endemic or become dormant after an outbreak, making it a challenge to know the true trajectory without the intervention. Secondly, without adequate design of controls and treatments, how can the estimated impacts be attributed to a given intervention? Thirdly, how do we assess costs saved by the intervention? Fourthly, given data uncertainty, would a stochastic simulation give better estimates than a deterministic one in solving for key variables? This paper addresses these issues and proposes solutions that bridge the gap between household level analysis and macro-level simulations in modelling the impact of animal diseases outbreaks.
An expost economic assessment of the intervention against highly pathogenic avian influenza in Nigeria
(Journal Article, 2014-04-01) Fadiga, M.L.; Okike, Iheanacho; Bett, Bernard K.
This study assesses the intervention against avian influenza in Nigeria. It applied a simple compartmental model to define endemic and burn-out scenarios for the risk of spread of HPAI in Nigeria. It followed with the derivation of low and high mortality risks associated to each scenario. The estimated risk parameters were subsequently used to stochastically simulate the trajectory of the disease, had no intervention been carried out. Overall, the intervention costs US$ 41 million, which was yearly dis- bursed in various amounts over the 2006-2010 period. The key output variables (incremental net benefit, disease cost, and benefit cost ratio) were estimated for each randomly drawn risk parameter. With a 12% annual discount rate, the results show that the intervention was economically justified under the endemic scenario with high mortality risk. On average, incremental benefit under this scenario amounted to US$ 63.7 million, incremental net benefit to US$27.2 million, and benefit cost ratio estimated to 1.75.
Impact of biosecurity training on farm management practice in Nigeria
(Report, 2013-07) Mmbone, Mildred; Bett, Bernard K.; Ndiwa, Nicholas N.
Transmission rate and reproductive number of the H5N1 highly pathogenic avian influenza virus during the December 2005-July 2008 epidemic in Nigeria
(Journal Article, 2014-02) Bett, Bernard K.; Henning, J.; Abdu, P.; Okike, Iheanacho; Poole, Elizabeth J.; Young, J.; Randolph, Thomas F.; Perry, Brian D.
We quantified the between-village transmission rate, β (the rate of transmission of H5N1 HPAI virus per effective contact), and the reproductive number, Re (the average number of outbreaks caused by one infectious village during its entire infectious period), of H5N1 highly pathogenic avian influenza (HPAI) virus in Nigeria using outbreak data collected between December 2005 and July 2008. We classified the outbreaks into two phases to assess the effectiveness of the control measures implemented. Phase 1 (December 2005–October 2006) represents the period when the Federal Government of Nigeria managed the HPAI surveillance and response measures, while Phase 2 (November 2006–July 2008) represents the time during which the Nigeria Avian Influenza Control and Human Pandemic Preparedness project (NAICP), funded by a World Bank credit of US$ 50 million, had taken over the management of most of the interventions. We used a total of 204 outbreaks from 176 villages that occurred in 78 local government areas of 25 states. The compartmental susceptible-infectious model was used as the analytical tool. Means and 95% percentile confidence intervals were obtained using bootstrapping techniques. The overall mean β (assuming a duration of infectiousness, T, of 12 days) was 0.07/day (95% percentile confidence interval: 0.06–0.09). The first and second phases of the epidemic had comparable β estimates of 0.06/day (0.04–0.09) and 0.08/day (0.06–0.10), respectively. The Re of the virus associated with these β and T estimates was 0.9 (0.7–1.1); the first and second phases of the epidemic had Re of 0.84 (0.5–1.2) and 0.9 (0.6–1.2), respectively. We conclude that the intervention measures implemented in the second phase of the epidemic had comparable effects to those implemented during the first phase and that the Re of the epidemic was low, indicating that the Nigeria H5N1 HPAI epidemic was unstable.
An ex post economic assessment of the intervention against highly pathogenic avian influenza in Nigeria
(Poster, 2012-08-18) Fadiga, M.L.; Okike, Iheanacho; Bett, Bernard K.
Identification of potential risk factors associated with highly pathogenic avian influenza subtype H5N1 outbreak occurrence in Lagos and Kano states, Nigeria, during the 2006-2007 epidemics
(Journal Article, 2013-02) Métras, Raphaëlle; Stevens, K.B.; Abdu, P.; Okike, Iheanacho; Randolph, Thomas F.; Grace, Delia; Pfeiffer, Dirk U.; Costard, Solenne
Highly pathogenic avian influenza HPAI H5N1 was first reported in Africa in 2006, in Nigeria. The country experienced severe outbreaks in 2006 and 2007, strongly affecting the poultry population. Current knowledge on potential risk factors for HPAI H5N1 occurrence in poultry farms in Nigeria is limited. Therefore, we conducted a case–control study to identify potential farm-level risk factors for HPAI H5N1 occurrence in two areas of the country that were affected by the disease in 2006 and 2007, namely the States of Lagos and Kano. A case–control study was conducted at the farm level. A convenience sample of 110 farms was surveyed. Data on farm characteristics, farm management and trade practices were collected. Logistic regression was used to identify factors associated with farms that confirmed positive for HPAI. Having a neighbouring poultry farm was identified as a potential risk factor for disease occurrence [OR, 5.23; 95% CI, (0.88–30.97); P-value = 0.048]. Farm staff washing their hands before handling birds was a protective factor [OR, 0.14; 95% CI, (0.05–0.37); P-value <0.001], as well as not allowing traders to enter the farm [OR, 0.23; 95% CI, (0.08–0.70); P-value = 0.008]. Our study highlighted the importance of trade and proximity between poultry farms in the epidemiology of HPAI H5N1 and the role of biosecurity in disease prevention in Kano and Lagos States. Despite the limitations owing to the sampling strategy, these results are consistent with other risk factor studies previously conducted on HPAI H5N1 in both Africa and other regions, suggesting similar risk factor patterns for HPAI H5N1 virus spread and substantiating current knowledge regarding the epidemiology of the disease. Finally, this study generated information from areas where data are difficult to obtain.
Independent impact assessment of the World Bank-funded Nigeria Avian Influenza Control and Human Pandemic Preparedness and Response Project (NAICP)
(Report, 2011-04-21) Perry, Brian D.; Randolph, Thomas F.; Bett, Bernard K.; Grace, Delia; Globig, A.; Fadiga, M.L.; Sones, Keith R.; Henning, J.; Pali, Pamela N.; Poole, Elizabeth J.; Hannah, H.; Ekanem, E.; Abdu, P.; Molokwu, C.
Incidence of highly pathogenic avian influenza H5N1 in Nigeria, 2005-2008
(Journal Article, 2013-06) Henning, J.; Bett, Bernard K.; Okike, Iheanacho; Abdu, P.; Perry, Brian D.
Outbreaks of highly pathogenic avian influenza (HPAI) H5N1 occurred in Nigeria between December 2005 and July 2008. We describe temporal and spatial characteristics of these outbreaks at State and Local Government Area (LGA) levels. A total of 25 of 37 States (67.6%; Exact 95% CI: 50.2–82.0%) and 81 of 774 LGAs (10.5%; Exact 95% CI: 8.4–12.8%) were affected by HPAI outbreaks over the period from 2005 to 2008. The incidence risk of HPAI outbreak occurrence at the State level was 5.6% (0.7–18.7%) for 2005, 50.0% (30.7–69.4%) for 2006, 54.5% (29.9–80.3%) for 2007 and 0% for 2008. Only very few LGAs experienced HPAI outbreaks within the affected States. The incidence risk of HPAI outbreak occurrence on a LGA level was 0.3% (0.0–0.9%) for 2005, 6.6% (4.9–8.6%) for 2006, 4.2% (2.9–6.0%) for 2007 and 0% for 2008. The mean period between farmers noticing HPAI outbreaks and reporting them to veterinary authorities, and between reporting HPAI outbreaks and the depopulation of infected premises, was for both 4.5 days; both periods also had medians of 1 day. We have estimated the spatially smoothed incidence risk for the whole outbreak period and identified the existence of a large corridor in the western part of Nigeria and a smaller corridor in south-eastern part, where the risk of HPAI occurrence was lower than in the rest of the country. The effect of HPAI control policies on the outbreaks patterns are discussed, as well as possible reasons why HPAI did not become endemic in Nigeria.

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