Antibody titer has positive predictive value for vaccine protection against challenge with natural antigenic-drift variants of H5N1 high-pathogenicity avian influenza viruses from Indonesia.

UNLABELLED: Vaccines are used in integrated control strategies to protect poultry against H5N1 high-pathogenicity avian influenza (HPAI). H5N1 HPAI was first reported in Indonesia in 2003, and vaccination was initiated in 2004, but reports of vaccine failures began to emerge in mid-2005. This study investigated the role of Indonesian licensed vaccines, specific vaccine seed strains, and emerging variant field viruses as causes of vaccine failures. Eleven of 14 licensed vaccines contained the manufacturer's listed vaccine seed strains, but 3 vaccines contained a seed strain different from that listed on the label. Vaccines containing A/turkey/Wisconsin/1968 (WI/68), A/chicken/Mexico/28159-232/1994 (Mex/94), and A/turkey/England/N28/1973 seed strains had high serological potency in chickens (geometric mean hemagglutination inhibition [HI] titers, ≥ 1:169), but vaccines containing strain A/chicken/Guangdong/1/1996 generated by reverse genetics (rg; rgGD/96), A/chicken/Legok/2003 (Legok/03), A/chicken/Vietnam/C57/2004 generated by rg (rgVN/04), or A/chicken/Legok/2003 generated by rg (rgLegok/03) had lower serological potency (geometric mean HI titers, ≤ 1:95). In challenge studies, chickens immunized with any of the H5 avian influenza vaccines were protected against A/chicken/West Java/SMI-HAMD/2006 (SMI-HAMD/06) and were partially protected against A/chicken/Papua/TA5/2006 (Papua/06) but were not protected against A/chicken/West Java/PWT-WIJ/2006 (PWT/06). Experimental inactivated vaccines made with PWT/06 HPAI virus or rg-generated PWT/06 low-pathogenicity avian influenza (LPAI) virus seed strains protected chickens from lethal challenge, as did a combination of a commercially available live fowl poxvirus vaccine expressing the H5 influenza virus gene and inactivated Legok/03 vaccine. These studies indicate that antigenic variants did emerge in Indonesia following widespread H5 avian influenza vaccine usage, and efficacious inactivated vaccines can be developed using antigenic variant wild-type viruses or rg-generated LPAI virus seed strains containing the hemagglutinin and neuraminidase genes of wild-type viruses. IMPORTANCE: H5N1 high-pathogenicity avian influenza (HPAI) virus has become endemic in Indonesian poultry, and such poultry are the source of virus for birds and mammals, including humans. Vaccination has become a part of the poultry control strategy, but vaccine failures have occurred in the field. This study identified possible causes of vaccine failure, which included the use of an unlicensed virus seed strain and induction of low levels of protective antibody because of an insufficient quantity of vaccine antigen. However, the most important cause of vaccine failure was the appearance of drift variant field viruses that partially or completely overcame commercial vaccine-induced immunity. Furthermore, experimental vaccines using inactivated wild-type virus or reverse genetics-generated vaccines containing the hemagglutinin and neuraminidase genes of wild-type drift variant field viruses were protective. These studies indicate the need for surveillance to identify drift variant viruses in the field and update licensed vaccines when such variants appear.

Development and application of a vaccination planning tool for avian influenza.

The vaccination planning tool for avian influenza supports evidence-based planning and preparedness for vaccinating poultry at national and regional levels. This study describes the development, testing, and application of a vaccination planning tool for H5N1 highly pathogenic avian influenza (HPAI) used in two South Asian countries. The tool consists of eight planning clusters, 37 planning elements, and 303 referenced planning criteria. Both countries attained a score of 52% among planning clusters as a measure of preparedness. The highest and lowest planning cluster scores included vaccination strategies and financial readiness, respectively. The comprehensive vaccination program was identified as the most-useful planning cluster for assessing preparedness, and 86% of participants indicated that the objectives of the planning tool were achieved. Based on these results, the planning tool provides a structured approach for decision makers to develop their national vaccination program for HPAI as part of an overall strategy for the progressive reduction and control of endemic influenza viruses in poultry.

Participatory disease surveillance and response in Indonesia: strengthening veterinary services and empowering communities to prevent and control highly pathogenic avian influenza.

The participatory disease surveillance and response (PDSR) approach to highly pathogenic avian influenza (HPAI) in Indonesia has evolved significantly from the participatory disease surveillance (PDS) system developed for rinderpest eradication in Africa and Pakistan. The first phase of the PDSR project emphasized the detection and control of HPAI by separate PDS and participatory disease response teams primarily in sector 4 poultry at the household level. Lessons learned during the first phase were taken into account in the design of the second phase of the project, which has sought to further strengthen management of disease prevention and control activities by improving technical approaches, increasing active participation of key stakeholders, including local and central governments, and focusing on the village level. The ongoing evolution of the PDSR program aims to establish a sustainable community-based program within provincial and district livestock services that enhances the prevention and control of not only HPAI, but also other zoonotic and priority animal diseases.

The Costs, Benefits and Human Behaviours for Antimicrobial Use in Small Commercial Broiler Chicken Systems in Indonesia.

There are growing concerns over the threat to human health from the unregulated use of antimicrobials in livestock. Broiler production is of great economic and social importance in Indonesia. This study used a structured questionnaire approach to explore the human behaviours and economic drivers associated with antimicrobial use in small commercial broiler systems in Indonesia (n = 509). The study showed that antimicrobial use was high with farmers easily able to access antimicrobials through local animal medicine, however, it was difficult for farmers to access veterinary advice on responsible antimicrobial use. The most significant finding was that the relative cost of antimicrobials was low, and farmers observed improvements in productivity rates from routine antimicrobial administration. However, farmers seldom kept detailed records on farm productivity or economic costs; this is a hurdle to undertaking a more detailed economic analysis of antimicrobial use. There is a need for further research on the cost-effectiveness of alternative methods of preventing disease and ensuring that feasible alternatives are easily available. Farm-level economics and securing the food supply chain need to be central to any future policy interventions to reduce antimicrobial use in broiler systems in Indonesia and this observation is relevant at a regional and global level.

Risk factors for H5 avian influenza virus prevalence on urban live bird markets in Jakarta, Indonesia-Evaluation of long-term environmental surveillance data.

In the re-emergence of Highly Pathogenic Avian Influenza (HPAI), live bird markets have been identified to play a critical role. In this repeated cross-sectional study, we combined surveillance data collected monthly on Jakarta's live bird markets over a five-year period, with risk factors related to the structure and management of live bird markets, the trading and slaughtering of birds at these markets, and environmental and demographic conditions in the areas where the markets were located. Over the study period 36.7% (95% CI: 35.1, 38.3) of samples (N = 1315) tested HPAI H5 virus positive. Using General Estimation Equation approaches to account for repeated observations over time, we explored the association between HPAI H5 virus prevalence and potential risk factors. Markets where only live birds and carcasses were sold, but no slaughtering was conducted at or at the vicinity of the markets, had a significantly reduced chance of being positive for H5 virus (OR = 0.2, 95% CI 0.1-0.5). Also, markets, that used display tables for poultry carcasses made from wood, had reduced odds of being H5 virus positive (OR = 0.7, 95% CI 0.5-1.0), while having at least one duck sample included in the pool of samples collected at the market increased the chance of being H5 virus positive (OR = 5.7, 95% CI 3.6-9.2). Markets where parent stock was traded, were more at risk of being H5 virus positive compared to markets where broilers were traded. Finally, the human population density in the district, the average distance between markets and origins of poultry sold at markets and the total rainfall per month were all positively associated with higher H5 virus prevalence. In summary, our results highlight that a combination of factors related to trading and marketing processes and environmental pressures need to be considered to reduce H5 virus infection risk for customers at urban live bird markets. In particular, the relocation of slaughter areas to well-managed separate locations should be considered.

Characterizing Antimicrobial Use in the Livestock Sector in Three South East Asian Countries (Indonesia, Thailand, and Vietnam).

A framework was developed to characterize the antimicrobial use/antimicrobial resistance complex in livestock systems in Indonesia, Vietnam, and Thailand. Farm profitability, disease prevention, and mortality rate reduction were identified as drivers toward antimicrobial use in livestock systems. It revealed that antimicrobial use was high in all sectors studied, and that routine preventative use was of particular importance to broiler production systems. Misleading feed labeling was identified as a hurdle to the collection of accurate antimicrobial use data, with farmers being unaware of the antimicrobials contained in some commercial feed. Economic analysis found that the cost of antimicrobials was low relative to other farm inputs, and that farm profitability was precariously balanced. High disease and poor prices were identified as potential drivers toward economic loss. The research indicates that antimicrobial use in small-scale poultry production systems improves feed conversion ratios and overall productivity. However, data were limited to quantify adequately these potential gains and their impacts on the food supply. During the study, all countries embraced and implemented policies on better management of antimicrobial use in livestock and surveillance of antimicrobial resistance. Future policies need to consider farm-level economics and livestock food supply issues when developing further antimicrobial use interventions in the region.

Identification of Indonesian clade 2.1 highly pathogenic influenza A(H5N1) viruses with N294S and S246N neuraminidase substitutions which further reduce oseltamivir susceptibility.

We have tested the in vitro susceptibility to the neuraminidase (NA) inhibitors of 96 highly pathogenic clade 2.1 A(H5N1) viruses from Indonesia, isolated between 2008 and 2011. HPAI virus samples obtained through the Influenza Virus Monitoring (IVM) surveillance program in Indonesia were tested for susceptibility to oseltamivir and zanamivir. The NAs of four viruses were identified as extreme outliers to oseltamivir, based on statistical analysis by box plots, with IC50 values ranging from 46 to 62 nM. The NAs of two of these viruses from Sumatra and Aceh, had an N294S substitution, while one virus from Sulawesi had an S246N NA substitution. The NAs of all four viruses showed a specific loss of slow binding to oseltamivir in an IC50 kinetics assay. As observed in our previous surveillance, there was only a minimal effect on the sensitivity to zanamivir or peramivir for these mutants or any of the other isolates tested. The continued circulation of subtype H5N1 viruses in avian species poses an on-going zoonotic threat. The fact that we continue to identify avian isolates with naturally occurring mutations conferring reduced oseltamivir susceptibility remains a concern, given oseltamivir will be a key antiviral in the event of a new pandemic emerging.

Surveillance at the molecular level: Developing an integrated network for detecting variation in avian influenza viruses in Indonesia.

Since 2006, Indonesia has used vaccination as the principal means of control of H5N1-HPAI. During this time, the virus has undergone gradual antigenic drift, which has necessitated changes in seed strains for vaccine production and associated modifications to diagnostic antigens. In order to improve the system of monitoring such viral evolution, the Government of Indonesia, with the assistance of FAO/OFFLU, has developed an innovative network whereby H5N1 isolates are antigenically and genetically characterised. This molecular surveillance network ("Influenza Virus Monitoring" or "IVM") is based on the regional network of veterinary diagnostic laboratories, and is supported by a web-based data management system ("IVM Online"). The example of the Indonesian IVM network has relevance for other countries seeking to establish laboratory networks for the molecular surveillance of avian influenza and other pathogens.

I222 Neuraminidase mutations further reduce oseltamivir susceptibility of Indonesian Clade 2.1 highly pathogenic Avian Influenza A(H5N1) viruses.

We have tested the susceptibility to neuraminidase inhibitors of 155 clade 2.1 H5N1 viruses from Indonesia, isolated between 2006-2008 as well as 12 clade 1 isolates from Thailand and Cambodia from 2004-2007 using a fluorometric MUNANA-based enzyme inhibition assay. The Thailand and Cambodian clade 1 isolates tested here were all susceptible to oseltamivir and zanamivir, and sequence comparison indicated that reduced oseltamivir susceptibility we observed previously with clade 1 Cambodian isolates correlated with an S246G neuraminidase mutation. Eight Indonesian viruses (5%), all bearing I222 neuraminidase mutations, were identified as mild to extreme outliers for oseltamivir based on statistical analysis by box plots. IC50s were from 50 to 500-fold higher than the reference clade 1 virus from Viet Nam, ranging from 43-75 nM for I222T/V mutants and from 268-349 nM for I222M mutants. All eight viruses were from different geographic locales; all I222M variants were from central Sumatra. None of the H5N1 isolates tested demonstrated reduced susceptibility to zanamivir (IC50s all <5 nM). All I222 mutants showed loss of slow binding specifically for oseltamivir in an IC50 kinetics assay. We identified four other Indonesian isolates with higher IC50s which also demonstrated loss of slow binding, including one virus with an I117V mutation. There was a minimal effect on the binding of zanamivir and peramivir for all isolates tested. As H5N1 remains a potential pandemic threat, the incidence of mutations conferring reduced oseltamivir susceptibility is concerning and emphasizes the need for greater surveillance of drug susceptibility.

Epidemiology of urban canine rabies, Santa Cruz, Bolivia, 1972-1997.

We analyzed laboratory data from 1972 to 1997 from Santa Cruz, Bolivia, to determine risk factors for laboratory canine samples' testing positive for Rabies virus (RABV). Of 9,803 samples, 50.7% tested positive for RABV; the number of cases and the percentage positive has dropped significantly since 1978. A 5- to 6-year cycle in rabies incidence was clearly apparent, though no seasonality was noted. Male dogs had significantly increased odds of testing positive for RABV (odds ratio [OR]=1.14), as did 1- to 2-year-old dogs (OR=1.73); younger and older dogs were at lower risk. Samples submitted from the poorer suburbs of the city were more likely to test positive for RABV (OR=1.71). Knowledge of the distribution of endemic canine rabies in an urban area will help focus control measures in a resource-poor environment.

Encuesta de la evaluación de la cobertura de vacunación antirabica canina en la ciudad de Santa Cruz, Noviembre de 1994 / Survey of antirabies canine vaccination in Santa Cruz, November 1994

La rabia canina permanece con una prevalencia en la ciudad de Santa Cruz. En Octubre de 1994 la Secretaría Nacional de Salud, implemento una campaña de vacunación contra la rabia canina, mediante la estrategia de vacunación de casa por casa. Este trabajo describe un estudio de evaluación de la cobertura de vacunación logrado en cinco Distritos de Santa Cruz y determina las fuentes de vacunación. Fueron encuestados un total de 1142 perros en 75 manzanas. En cuanto a los distritos la cobertura estimada fue entre 91 y 95 y de 81el restante. La cobertura del sector privado por distrito fue entre 13 y 31. Los autores consideran que ésta cobertura es suficiente para disminuír la incidencia de rabia canaina, pero ésta, debe complementarse con medidas de vigilancia y control de focos.