Risk Assessment of the Introduction of H5N1 Highly Pathogenic Avian Influenza as a Tool to be Applied in Prevention Strategy Plan

Abstract

Risks of the introduction of highly pathogenic avian influenza (HPAI) H5N1 through migratory birds to the main wintering site for wild birds in southern Brazil and its consequences were assessed. Likelihoods were estimated by a qualitative scale ranging from negligible to high. Northern migrants that breed in Alaska and regularly migrate to South America (primary Charadriiformes) can have contact with birds from affected areas in Asia. The likelihood of the introduction of HPAI H5N1 through migratory birds was found to be very low as it is a probability conditioned to successful transmission in breeding areas and the probabilities of an infected bird migrating and shedding the virus as far as southern Brazil. The probability of wild species becoming exposed to H5N1-infected birds is high as they nest with northern migrants from Alaska, whereas for backyard poultry it is moderate to high depending on proximity to wetlands and the presence of species that could increase the likelihood of contact with wild birds such as domestic duck. The magnitude of the biological and economic consequences of successful transmission to poultry or wild birds would be low to severe depending on the probability of the occurrence of outbreak scenarios described. As a result, the risk estimate is greater than negligible, and HPAI H5N1 prevention strategy in the region should always be carefully considered by the veterinary services in Brazil.

A review of qualitative risk assessment in animal health: Suggestions for best practice

“…Published matrices using a multiplicative risk framework varied in the RAs reviewed here. One of the most commonly used adheres to the principle that the product of two probabilities is always equal to the lowest probability ( Table 3 ) ( 6 , 9 , 30 , 40 , 42 , 46 ). This matrix defines a likelihood estimate for any binary combination of conditional events but does not allow for the product of multiple conditional probabilities to be lower than the lowest value of the individual probabilities.…”

“…Other uses include microbial risk assessments (MRAs) and/or farm-to-consumption RAs, [e.g., ( 4 , 5 )], and rapid veterinary RAs (VRAs), which can form part of a national disease outbreak response. Risk assessments can also perform the role of decision support tools to assist decision makers in the selection and application of the most efficient control and risk mitigation measures during an animal disease outbreak ( 6 , 7 ).…”

An assessment on potential risk pathways for the incursion of highly pathogenic avian influenza virus in backyard poultry farm in Bangladesh

“…Qualitative descriptors were used as adjectives to determine the likelihood and consequences associated with RPs (Tables-1 and 2). To reduce the possibility of bias, expert groups discussed, reviewed, and finally adopted descriptors with few modifications from Corbellini et al [21]. Available at www.veterinaryworld.org/Vol.13/October-2020/9.pdf c. Hygienic measures (cleaning and spraying disinfectant) along RP-3 d. Hygienic disposal of slaughtered poultry remnant or waste along RP-4.…”

“…The function of likelihood/ probabilities and consequences was used to estimate the risk. Earlier described likelihood/probabilities and consequences were used in the risk assessment with minor modifications [21]. A table was generated during analysis (Table -3) based on a score related to the qualitative descriptors.…”

“…Migratory or aquatic birds are known reservoirs of avian influenza virus [16]. Each year thousands of wild birds migrate to Bangladesh from countries as far as Siberia for wintering purposes [21]. They frequently share food sources and water bodies with backyard poultry and provoke chances for HPAIV introduction into a new susceptible host through direct or indirect contacts.…”