Ranking wild bird species and their settlements for avian influenza virus surveillance in Cuba

Introduction

Since 2022, a completely unprecedented highly pathogenic avian influenza (HPAI) situation, in terms of outbreak occurrence and worldwide distribution, has been taking place, affecting domestic and wild birds, and some terrestrial and aquatic mammals. This reflects a change in the epidemiology and ecology of the virus, posing a threat to animal and public health, food security, and biodiversity (11. Swayne D. E, Sims L, Brown I, Harder T, Stegeman A, Abolnik C, Delgado M, Awada L, Pavade G TG. Strategic challenges in the global control of High Pathogenicity Avian Influenza [Internet]. Paris; 2023. (90 SG/8). Disponible en: https://www.woah.org/app/uploads/2023/05/a-90sg-8.pdf ,22. Shi J, Zeng X, Cui P, Yan C, Chen H. Alarming situation of emerging H5 and H7 avian influenza and effective control strategies. Emerg Microbes Infect. 2023;12(1):2155072.). Such dramatic change includes massive infection events in some mammalian species, sometimes with clear evidence of spillover and transmission between congeners (33. Agüero M, Monne I, Sánchez A, Zecchin B, Fusaro A, Ruano MJ, et al. Highly pathogenic avian influenza A(H5N1) virus infection in farmed minks, Spain, October 2022. Eurosurveillance. 2023;28(3).-66. Gilbertson B, Subbarao K. Mammalian infections with highly pathogenic avian influenza viruses renew concerns of pandemic potential. J Exp Med. 2023;220(8):e20230447.), which reinforces pandemic concerns. In addition, it implies a renewed need to better understand introduction, spread and potential impact of HPAI to improve control and mitigate negative outcomes.

The ability of waterfowl, among which are the main reservoirs of avian influenza viruses (AIVs), to cover large geographic distances when migrating, combined with the substantial prevalence and diversity of AIVs they may carry, provides the opportunity for novel AIVs to emerge through co-infection events, as well as through the introduction of AIVs from different regions into immunologically naïve populations (77. Bevins SN, Pedersen K, Lutman MW, Baroch JA, Schmit BS, Kohler D, et al. Large-scale avian influenza surveillance in wild birds throughout the United States. PLoS One. 2014;9(8):e104360.). There is growing evidence that HPAIVs are endemic in the avian reservoir, adding complexity to their eradication (88. Ramey AM, Hill NJ, DeLiberto TJ, Gibbs SEJ, Camille Hopkins M, Lang AS, et al. Highly pathogenic avian influenza is an emerging disease threat to wild birds in North America. Vol. 86, Journal of Wildlife Management. 2022. p. e22171.). This may indicate a higher risk of disease occurrence in countries connected with migratory flyways.

Surveillance of AIVs in live wild birds is expensive and difficult, involving substantial labor and costs (99. Globig A, Staubach C, Beer M, Köppen U, Fiedler W, Nieburg M, et al. Epidemiological and ornithological aspects of outbreaks of highly pathogenic avian influenza virus H5N1 of Asian lineage in wild birds in Germany, 2006 and 2007. Vol. 56, Transboundary and Emerging Diseases. 2009. p. 57-72.). Given that the prevalence of infection in wild birds is generally low and can vary both temporally and spatially within a species (1010. Kent CM, Bevins SN, Mullinax JM, Sullivan JD, Prosser DJ. Waterfowl show spatiotemporal trends in influenza A H5 and H7 infections but limited taxonomic variation. Ecol Appl. 2023;33(7).,1111. Ruiz S, Jimenez-Bluhm P, Di Pillo F, Baumberger C, Galdames P, Marambio V, et al. Temporal dynamics and the influence of environmental variables on the prevalence of avian influenza virus in main wetlands in central Chile. Transbound Emerg Dis. 2021;68(3).), it is difficult to make an initial assessment of the most important target species and sites for surveillance. Further, AIV surveillance programs need to be locally adapted to the avian population at each study region (1212. Carter D, Link P, Walther P, Ramey A, Stallknecht D, Poulson R. Influenza A Prevalence and Subtype Diversity in Migrating Teal Sampled Along the United States Gulf Coast. Avian Dis. 2019;63(sp1):165.,1313. Wilcox BR, Knutsen GA, Berdeen J, Goekjian V, Poulson R, Goyal S, et al. Influenza-A Viruses in Ducks in Northwestern Minnesota: Fine Scale Spatial and Temporal Variation in Prevalence and Subtype Diversity. PLoS One. 2011;6(9):e24010.). Additionally, viral strains from different host origin may differ in their affinity for either the digestive or respiratory tract (1414. Hénaux V, Samuel MD. Avian influenza shedding patterns in waterfowl: Implications for surveillance, environmental transmission, and disease spread. J Wildl Dis. 2011;47(3):566-78.,1515. Wille M, Lisovski S, Roshier D, Ferenczi M, Hoye BJ, Leen T, et al. Strong host phylogenetic and ecological effects on host competency for avian influenza in Australian wild birds. Proc R Soc B Biol Sci. 2023;290(1991).). Therefore, ideal sampling and monitoring programs involve both cloacal and oropharyngeal samples (preferably not mixed), increasing cost and resources. There are advances in environmental sampling of AIVs (1616. Ramey AM, Reeves AB, Drexler JZ, Ackerman JT, De La Cruz S, Lang AS, et al. Influenza A viruses remain infectious for more than seven months in northern wetlands of North America. Proc R Soc B Biol Sci. 2020;287(1934):20201680.), but there are no studies in warmer latitudes.

A coordinated annual surveillance system with a global perspective does not necessarily require participation from every country (1717. Machalaba CC, Elwood SE, Forcella S, Smith KM, Hamilton K, Jebara KB, et al. Global avian influenza surveillance in wild birds: a strategy to capture viral diversity. Emerg Infect Dis. 2015;21(4):e1-7.). On the other hand, the intensity of surveillance in waterfowl alone does not prevent the occurrence of outbreaks in poultry, as evidenced by some recent epidemics with HPAI H5Nx subtypes, even when there was intensive surveillance of its circulation in wild birds. In this context, resource allocation could be prioritized to provide sustained surveillance in a few targeted locations and in specific seasons that maximize information on viral diversity relevant to potential spread (e.g., high-risk species, species interfaces, major staging and migration stopover sites, and reassortment hotspots) (1818. Franklin AB, Bevins SN, Ellis JW, Miller RS, Shriner SA, Root JJ, et al. Predicting the initial spread of novel Asian origin influenza A viruses in the continental USA by wild waterfowl. Transbound Emerg Dis. 2019;66(2):705-14.). The need of both geographic and species prioritization of sampling efforts to reach a reasonable cost/benefit ratio of wild bird surveillance could be addressed by targeting areas and species most likely to harbor AIVs.

Cuba, within the Caribbean region, could likely be of major importance to conduct virus surveillance of global interest. First, the Cuban archipelago, holding 48 % of the emerged land in the Caribbean, is an important stopover and wintering site for about 193 wild bird species (1919. Aguilar S, Manica LT, Acosta M, Castro R, Hernández Z, González A, et al. Spatio-Temporal Patterns of Waterbird Assemblages in Cuba’s South Coast Wetlands: Conservation Implications. Wetlands. 2020;40(2):407-19.). Two of the four North American flyways (the Atlantic and the Mississippi flyways) used by Nearctic migrant birds extensively affects the Cuban territory. Thus, Cuba is not only an important wintering area for migrant birds from North America, but is also a very important staging area for birds moving to other Caribbean islands or birds migrating further south (2020. Acosta Cruz M, Mugica Valdés L. Evaluación general de las poblaciones de aves acuáticas de Cuba. 2006 [citado 5 de septiembre de 2019]; Disponible en: http://repositorio.geotech.cu/xmlui/handle/1234/1403 ). In addition, Cuba holds an important network of 28 Important Bird Areas (IBAs), which is an international designation that highlight critical sites for bird conservation (2121. RAMSAR. The List of Wetlands of International Importance. 2024 [citado 19 de julio de 2024];(17):1-57. Disponible en: https://www.ramsar.org/sites/default/files/2023-08/sitelist.pdf ). Specifically, 12 of these areas hold globally significant congregations of seabirds and waterbirds (2222. Aguilar S, Denis D, Parada A, Centro Nacional de Áreas Protegidas (Cuba) A, BirdLife International. Important Bird Area Programme. A, Serrano A, et al. Áreas importantes para la conservación de las aves en Cuba [Internet]. Editorial. García RC, editor. Habana: Centro Nacional de Áreas Protegidas (CNAP); 2010 [citado 2 de octubre de 2019]. 136 p. Disponible en: http://repositorio.geotech.cu/jspui/handle/1234/2215 ).

The long and narrow shape of the Cuban archipelago with an insular platform where shallow waters and mangroves abound, facilitate the existence of large coastal wetlands which provide habitat for important breeding and non-breeding waterbird populations (2020. Acosta Cruz M, Mugica Valdés L. Evaluación general de las poblaciones de aves acuáticas de Cuba. 2006 [citado 5 de septiembre de 2019]; Disponible en: http://repositorio.geotech.cu/xmlui/handle/1234/1403 ,2323. Blanco Rodríguez P, Vilella FJ, Oria BS. Waterfowl in Cuba: Current status and distribution. Wildfowl. 2014;0(0):498-511.). In summary, wetlands stand for near 15 % of the country area with two thirds of this area designated as Ramsar sites (2121. RAMSAR. The List of Wetlands of International Importance. 2024 [citado 19 de julio de 2024];(17):1-57. Disponible en: https://www.ramsar.org/sites/default/files/2023-08/sitelist.pdf ).

Habitat availability for waterbirds in Cuba is extended by natural and man-made freshwater bodies, including rice-growing areas, where these birds forage (2424. Acosta M, Mugica L, Blanco D, Löpez-Lanüs B, Antunes Dias R, Doodnath LW, et al. Birds of rice fields in the Americas. Waterbirds. 2010;33(SPEC.ISSUE.1):105-22.). The ecology of the AIVs in rice paddy fields involves an intricate web of drivers for AI occurrence (2525. Sievers BL, Hyder S, Claes F, Karlsson EA. Ingrained: Rice farming and the risk of zoonotic spillover, examples from Cambodia. One Heal. 2024;18:100696.). From the perspective of consequences of AIVs incursion, poultry production in Cuba is an important component of livestock economy and represents over 12.8 million individuals, mostly laying hens (56.7%), with their own genetics (2626. ONEI. Anuario Estadístico de Cuba 2022. Edición 2023.Capitulo 9. Agricultura, Ganadería, Silvicultura y Pesca. [Internet]. 2023. Disponible en: https://www.onei.gob.cu/sites/default/files/publicaciones/2024-04/09-agropecuario-2022_0.pdf ). Consequently, this amount of AIV susceptible population, combined with areas suitable for the main reservoir, may create wild bird-poultry interfaces from which HPAI could occurs and spread. The possibility of AIV incursion in Cuba is not only theoretical, as evidenced by the recent event of infection by HPAI virus H5N1 in zoo birds (2727. WAHIS. Notificación Evento 4895. 2023 [citado 3 de septiembre de 2024]. Cuba - Influenza de tipo A de alta patogenicidad (Inf. por los virus de la) (aves que no sean de corral, incluyendo las silvestres) (2017-) - Informe de seguimiento 10 [FINAL]. Disponible en: https://wahis.woah.org/#/in-review/4895?fromPage=event-dashboard-url ).

Considering the need of strategic allocation of resources for surveillance, the aim of this study was, first, to narrow the number of species and settlements where AIVs could be found in Cuba, by ranking those more probable exposed, in order to prioritize further effort for wild bird surveillance in a cost-effective way. This goal is hypothesized attainable by combining available published data on observed patterns of AIV prevalence in birds in America with local variables of distribution range of main migrating wild birds, abundance and host community composition.

Materials and methods

Results

The frequencies of species with high AIV prevalence varied through the locations studied during migration but without a regular pattern (Figure 1). The man-made dams “Presa Bacunagua”, “Presa Los Palacios”, “Presa de la Juventud”, “Estación de Alevinaje”, “Presa Niña Bonita”, and “Presa Ejército Rebelde” were only sampled during fall migration; Interestingly, they showed frequency values compared to natural wetlands.

The maximum abundance of birds showed large differences among locations. Bird abundance was higher during the fall migration period, except for “Canales del Hanábana”, where higher values were observed during spring migration (Figure 2). Los Palacios was the location with the highest number of birds with values twice as high as “Ciénaga de Zapata”, the second most important wetland in terms of bird abundance.

The prevalence-weighted approach for species (Figure 3) showed a distribution pattern allocating species as very high, high, moderate or low indexes. According to the rank order index, the top five species belonged to the family Anatidae, followed by the American Coot of the family Rallidae and, sequentially, two species, the Laughing Gull of the family Laridae and the Ruddy Turnstone of the family Scolopacidae, which were of intermediate rank. The differences among species were marked, underlining Blue-Winged Teal (BWTE), followed by two diving duck species Lesser Scaup and Ring-necked Duck. Anatidae was the best represented family among the species identified by this index, totalling 10 out of 21 species.

The ranking of the sites (Figure 4) showed indexes that may be considered very high, high, moderate or low. In this case, Los Palacios was of first order (very high) with notable difference from the rest of the sites. Ciénaga de Zapata with second order rank (high) differed widely from the rest of localities, both harboring the maximum number of BWTE in the country, species with high prevalence values of AIV during spring migration followed by Delta del Cauto El Mango in Birama Swamp, Canales del Hanábana and San Felipe ranked as moderate. Tunas de Zaza and the rest of the wetlands were considered less important, as they showed the lowest values.

According to local studies and AIVs reported in the literature, 27 species of wild migratory birds may be of interest for avian influenza surveillance in Cuba (Table 2). These species are distributed in six orders and nine families.

Additionally, nine other species (aquatic and terrestrial) were identified as being of potential interest for surveillance but lacking local ecological data (Table 3).

In terms of abundance, BWTE clearly evidenced the wild duck poultry interface. (Figure 5)

Discussion

This study was the first, to the authors’ knowledge, to rank the suitability of both species and sites for AIV surveillance within the Caribbean region, by considering prevalence-weighted ornithological data to allocate bird species and, by extension, sites in a suitability index for surveillance effectiveness, risk assessment and potential risk management outcomes. Prosser et al. (3333. Prosser DJ, Palm EC, Takekawa JY, Zhao D, Xiao X, Li P, et al. Movement analysis of free-grazing domestic ducks in Poyang Lake, China: a disease connection. Int J Geogr Inf Sci. 2016;30(5):869-80.) reveal that adding prevalence to the waterfowl abundance layer is effective in capturing complexity between these two variables at the species level. In addition, poultry density was considered as an ancillary layer, which may bring insights on the Cuban wild birds-poultry interface.

Given that Cuba holds about 48 % of the emerged land in the Caribbean islands and it is an important migration and stopover site in the region, an effective surveillance and risk assessment may have regional implications that benefit other Caribbean islands and countries in South America. Every year, many migratory bird species first pass through the Cuban archipelago during fall migration to continue southward or to countries to the east, and BWTE is one of the best known examples (1919. Aguilar S, Manica LT, Acosta M, Castro R, Hernández Z, González A, et al. Spatio-Temporal Patterns of Waterbird Assemblages in Cuba’s South Coast Wetlands: Conservation Implications. Wetlands. 2020;40(2):407-19.). On the other hand, the methodology used in this assessment can be extended to other countries participating in the (Caribbean Waterbird Census), a regional program implemented since 2012 in the Caribbean region that annually updates the ornithological community using most local wetland ecosystems (3434. BirdsCaribbean. Caribbean Waterbird Census Program [Internet]. 2024 [citado 19 de julio de 2024]. Disponible en: https://www.birdscaribbean.org/our-work/caribbean-waterbird-census-program/ ).

The prominent use of Cuban ecosystems during fall migration relative to spring migration has been noted and explained by the use of alternative migratory flyways for return not including Cuba (2828. Mugica, L., Acosta, M., Aguilar, S., Hernández, N., Perez, A., De la Cruz, J.M., Hernández, Z., Castro, R., González, A., Navarro, D., Inguanzo, R., Rodriguez, A., Labrada O. & López M. Resultados del Programa de aves acuáticas y marinas. En: Hernández Ávila A, editor. Estado actual de la biodiversidad marino-costera en la región de los Archipiélagos del Sur de Cuba. La Habana, Cuba: Impresos Dominicanos s.r.l; 2014. p. 101-18.). Therefore, in general, the probability of AIV incursion and detection would be higher during fall migration. Nevertheless, one of the sites studied (Canales del Hanábana) had a higher population of waterfowl during spring migration.

The marked differences in rank among species could be an effect of combined variables (abundance, frequency and prevalence) to infer importance as a product of probabilities. Therefore, the approach followed may have sufficient differentiating power. Prevalence-weighted waterbird abundance has been used as a proxy for the “effective” waterbird population that may be shedding virus into the environment and potentially exposing susceptible poultry and domestic birds to AIVs (3333. Prosser DJ, Palm EC, Takekawa JY, Zhao D, Xiao X, Li P, et al. Movement analysis of free-grazing domestic ducks in Poyang Lake, China: a disease connection. Int J Geogr Inf Sci. 2016;30(5):869-80.). However, the rank used in the current study also included frequency (occasions in which a particular species was observed during the study period) to derive significance, which may also indicate the length of the risk of exposure to AIVs.

In the case of Mallard ducks, for instance, the prevalence reported in the literature is very high (3535. Trovão NS, Nolting JM, Slemons RD, Nelson MI, Bowman AS. The Evolutionary Dynamics of Influenza A Viruses Circulating in Mallards in Duck Hunting Preserves in Maryland, USA. Microorganisms. 2020;9(1):40.), but the species is very rare in Cuba (3636. Garrido, O.H. and Kirkconnell A. Aves de Cuba. Cornell University Press. Ithaca, New York. USA; 2011. 287 p.) and it was not reported in any of the wetlands sampled, thus the species does not represent a threat to Cuba.

The predominant presence of the Anatidae and Laridae families within the highest prevalence-weighted index was consistent with the existing knowledge on Anseriformes and Charadriiformes species as main AIV reservoirs (3232. Olsen B, Munster VVJ, Wallensten A, Waldenström J, Osterhaus ADMEA, Fouchier RAM, et al. Global patterns of influenza a virus in wild birds. Science. 2006;312(5772):384-8.). Particularly the highest prevalence-weighted index of BWTE anticipated its use as a sentinel species with a high probability of detecting AIVs, which is consistent with evidence-based studies showing higher prevalence in dabbling ducks (77. Bevins SN, Pedersen K, Lutman MW, Baroch JA, Schmit BS, Kohler D, et al. Large-scale avian influenza surveillance in wild birds throughout the United States. PLoS One. 2014;9(8):e104360.,3737. Ramey AM, Poulson RL, González-Reiche AS, Wilcox BR, Walther P, Link P, et al. Evidence for seasonal patterns in the relative abundance of avian influenza virus subtypes in blue-winged teal (Anas discors). J Wildl Dis. 2014;50(4):916-22.).

BWTE is an early migrant that due to its “catchability” would be an accessible hunter-harvested prey. This coincides with information obtained through a survey of Cuban wild bird hunters, who rank BWTE as the most hunted species (3838. Delgado-Hernández B, Mugica L, Acosta M, Pérez F, Montano D de las N, Abreu Y, et al. Knowledge, Attitudes, and Risk Perception Toward Avian Influenza Virus Exposure Among Cuban Hunters. Front Public Heal. 2021;9:644786.). It is of paramount importance because surveillance sensitivity is usually higher in hunter-harvested birds with respect to other sources (3939. Wade D, Ashton-Butt A, Scott G, Reid SM, Coward V, Hansen RDE, et al. High pathogenicity avian influenza: targeted active surveillance of wild birds to enable early detection of emerging disease threats. Epidemiol Infect. 2023;151:e15.), which contributes to the cost-effectiveness analysis of surveillance.

Another option to improve AIVs detectability is sampling hatch-year or juvenile birds, which are more likely to be naïve to AI virus and more abundant due to the high annual population turnover of these species (4040. Brown JD, Poulson R, Stallknecht DE. Wild bird surveillance for avian influenza virus. In Animal Influenza Virus. En: Spackman E, editor. Animal Influenza Virus. New York, NY: Humana Press; 2014. p. 69-81.). Despite, overall population prevalence may be biased targeting only juveniles, AIV presence/absence may be confirmed more cost-effectively.

Although prevalence-weighted index of Laughing gull slightly precedes that of Ruddy Turnstone, the latter species is distinguished among Charadriiformes for bringing most of AIV isolates with regard to sympatric shorebirds, but limited to Delaware Bay, noted as an ecological hotspot (4141. Brown JD, Poulson R, Stallknecht DE. Wild bird surveillance for avian influenza virus. Methods Mol Biol. 2014;1161:69-81.). In other worldwide locations, the prevalence of this shorebird is generally low (3232. Olsen B, Munster VVJ, Wallensten A, Waldenström J, Osterhaus ADMEA, Fouchier RAM, et al. Global patterns of influenza a virus in wild birds. Science. 2006;312(5772):384-8.). Nonetheless, the findings of some Charadriiformes species with moderate prevalence-weighted index in the current study, add complexity to the risk of AIV spillover. The seasonal prevalence of influenza viruses in shorebirds is reversed as compared with ducks, with higher virus prevalence (~14%) during spring migration (4242. Krauss S, Walker D, Pryor SP, Niles L, Chenghong L, Hinshaw VS, et al. Influenza A viruses of migrating wild aquatic birds in North America. Vector-Borne Zoonotic Dis. 2004;4(3):177-89.).

Unpublished data obtained by the authors in “Ciénaga de Zapata” have shown that shorebird abundance increases in February and March, during spring migration. This period is coincident with the dry season in Cuba and more shallow coastal lagoons are accessible to them. Such pattern, besides favoring virus persistence, could extend the period with risk of transmission in the wild bird-poultry interface. Additionally, several Charadriiformes species nest from May to August in the Caribbean region, with major abundance in Cuba (2323. Blanco Rodríguez P, Vilella FJ, Oria BS. Waterfowl in Cuba: Current status and distribution. Wildfowl. 2014;0(0):498-511.).

The relative low prevalence-weighted index of Wood Duck was related to its low abundance (results not showed). However, the resident behavior of this species Ducks may maintain virus into the environment for longer time than migrant species. In fact, Henaux et al. (4343. Hénaux V, Samuel MD, Dusek RJ, Fleskes JP, Ip HS. Presence of Avian Influenza Viruses in Waterfowl and Wetlands during Summer 2010 in California: Are Resident Birds a Potential Reservoir? PLoS One. 2012;7(2):e31471.) demonstrated that resident populations of Wood Ducks, even at low densities and unfavorable environmental conditions, did not prevent low pathogenic avian influenza virus (LPAIV) circulation during summer in California wetlands, while the American Coot is an opposite example.

Despite H5 and H7 subtypes are those of major concern for poultry, the inference of the prevalence-weighted index was based on overall prevalence of wild bird species to influenza A virus. Nonetheless, it is thought the approach followed could capture the importance of AIVs circulation in wild birds no limited to H5 and H7 subtypes. In fact, several avian influenza virus subtypes other than H5Nx and H7Nx have the ability to infect mammals, including humans (4444. Everest H, Hill S, Daines R, Sealy J, James J, Hansen R, et al. The Evolution, Spread and Global Threat of H6Nx Avian Influenza Viruses. Viruses. 2020;12(6):673.-4646. Sit THC, Sun W, Tse ACN, Brackman CJ, Cheng SMS, Tang AWY, et al. Novel Zoonotic Avian Influenza Virus A(H3N8) Virus in Chicken, Hong Kong, China. Emerg Infect Dis. 2022;28(10):2009-15.) with zoonotic/pandemic concern. In addition, positive findings for H5 and H7 subtype viruses are commonly reported without denominator data, and the particular relative risk for spillover is difficult to assess.

Site selection criteria revealed a high importance for the prioritization of wild bird surveillance. The highest rank of Los Palacios depends on foremost levels of waterbird abundance observed in this location where there is a close relationship between wetlands and rice fields (2828. Mugica, L., Acosta, M., Aguilar, S., Hernández, N., Perez, A., De la Cruz, J.M., Hernández, Z., Castro, R., González, A., Navarro, D., Inguanzo, R., Rodriguez, A., Labrada O. & López M. Resultados del Programa de aves acuáticas y marinas. En: Hernández Ávila A, editor. Estado actual de la biodiversidad marino-costera en la región de los Archipiélagos del Sur de Cuba. La Habana, Cuba: Impresos Dominicanos s.r.l; 2014. p. 101-18.). The proximity of rice cultivation to roosting, resting and refuge areas in Cuban coastal wetlands as in the case of “Los Palacios”, is an important factor that allows birds to use both ecosystems to provide their daily needs with relatively low energetic cost (2020. Acosta Cruz M, Mugica Valdés L. Evaluación general de las poblaciones de aves acuáticas de Cuba. 2006 [citado 5 de septiembre de 2019]; Disponible en: http://repositorio.geotech.cu/xmlui/handle/1234/1403 ). In addition, this western location, due of its geographical position and the size of the wetland, should be an important starting setting for waterbird arrival to Cuba during fall migration according to the dynamic of waterbird abundance thus, facilitating early warning.

Indeed, two Cuban rice plantations (“Humedal Sur de Pinar del Río” & “Humedal del Sur de Sancti Spíritus”), both included in this study, are declared as IBAs (2121. RAMSAR. The List of Wetlands of International Importance. 2024 [citado 19 de julio de 2024];(17):1-57. Disponible en: https://www.ramsar.org/sites/default/files/2023-08/sitelist.pdf ). Ninety-seven bird species, most of them (74 %) totally or partially migratory, have been reported using rice fields and surrounding areas in Cuba (2020. Acosta Cruz M, Mugica Valdés L. Evaluación general de las poblaciones de aves acuáticas de Cuba. 2006 [citado 5 de septiembre de 2019]; Disponible en: http://repositorio.geotech.cu/xmlui/handle/1234/1403 ).

In terms of virus incursion consequences, factors associated with the occurrence of HPAI such as poultry population, human and road density (4747. Stevens KB, Gilbert M, Pfeiffer DU. Modeling habitat suitability for occurrence of highly pathogenic avian influenza virus H5N1 in domestic poultry in Asia: A spatial multicriteria decision analysis approach. Spat Spatiotemporal Epidemiol. 2013;4(1):1-14.), are scarce in “Ciénaga de Zapata”. Consequently, its priority for surveillance as a method of early warning is reduced. On the contrary, “Los Palacios” could be further prioritized, because poultry production areas and rice fields neighbor it. For similar reason, “Tunas de Zaza” ranked sixth, requires additional considerations in the prioritization process. Active surveillance for avian influenza in Cuba is carried out under considerations of risk of disease occurrence that take into account the potential magnitude of losses (4848. Montano-Valle D d/l Nieves, Percedo MI, Rodríguez SV, Fonseca O, Centelles Y, Ley O, Abreu Y, Delgado B, Capdevila Y, Regis-Santoro K, Quesada T, Peláez M AP. Influenza aviar. Oportunidades de mejora del sistema de vigilancia activa basado en riesgo en Cuba. Rev Salud Anim. 2020;42(3).,4949. Pineda Medina, D., Miranda Cabrera, I., de las Nieves Montano Valle, D., Delgado Hernandez, B., Abreu Jorge, Y., Alfonso P. Stochastic simulation of the spread of highly pathogenic avian influenza in Cuba. Rev Salud Anim. 2023;45.).

Cuba has not initiated active surveillance on AIV in wild birds, but the current work could be a starting point considering the existence of laboratory infrastructure. Given that most of countries are typically able to allocate a limited number of resources for sample collection, the question of how those limited resources may be most efficiently applied to maximize the probability of detection of an infectious agent could be critical to further improving prevention programs. In this regard, the prospective targeting of species and locations of foremost importance may allow a more effective planning of resources.

The remarkable distance of BWTE prevalence-weighted index from other species places it as the most important for deciphering the wild duck-poultry interface, including locations with the greatest potential for AIV spillover to poultry and domestic birds. Other studies in Cuba model the transmission from waterbird to poultry (5050. Montano Valle D de las N, Berezowski J, Delgado-Hernández B, Hernández AQ, Percedo-Abreu MI, Alfonso P, et al. Modeling transmission of avian influenza viruses at the human-animal-environment interface in Cuba. Front Vet Sci. 2024;11:1415559.), but in a general way, without discriminating the importance of different wild bird species as a reservoirs.

Transmission mechanisms at the wild bird-poultry interface can be complex, as both wild waterfowl and terrestrial birds can be involved. (5151. Teitelbaum CS, Casazza ML, Overton CT, Sullivan JD, Matchett EL, McDuie F, et al. Potential use of poultry farms by wild waterfowl in California’s Central Valley varies across space, times of day, and species: implications for influenza transmission risk. Ecography (Cop). 2024;,5252. Cerda-Armijo C, de León MB, Ruvalcaba-Ortega I, Chablé-Santos J, Canales-del-Castillo R, Peñuelas-Urquides K, et al. High Prevalence of Avian Influenza Virus Among Wild Waterbirds and Land Birds of Mexico. Avian Dis. 3 de enero de 2020;64(2):135.). Given the complexity of avian influenza control (5353. Simancas-Racines A, Cadena-Ullauri S, Guevara-Ramírez P, Zambrano AK, Simancas-Racines D. Avian Influenza: Strategies to Manage an Outbreak. Pathogens. 2023;12(4):610.), countries free of the disease, as is the case of Cuba, need to strengthen resilience capacities, for which it is appropriate to anticipate the risk of occurrence of the disease. Those locations that may form a wild bird-poultry interface must be prioritized in a broad sense (risk management through enhanced biosecurity and surveillance for early alert). Therefore, current outputs add knowledge to previous studies aimed at capacity building for early warning and resilience in Cuba against this global hazard (3838. Delgado-Hernández B, Mugica L, Acosta M, Pérez F, Montano D de las N, Abreu Y, et al. Knowledge, Attitudes, and Risk Perception Toward Avian Influenza Virus Exposure Among Cuban Hunters. Front Public Heal. 2021;9:644786.,4848. Montano-Valle D d/l Nieves, Percedo MI, Rodríguez SV, Fonseca O, Centelles Y, Ley O, Abreu Y, Delgado B, Capdevila Y, Regis-Santoro K, Quesada T, Peláez M AP. Influenza aviar. Oportunidades de mejora del sistema de vigilancia activa basado en riesgo en Cuba. Rev Salud Anim. 2020;42(3).,5050. Montano Valle D de las N, Berezowski J, Delgado-Hernández B, Hernández AQ, Percedo-Abreu MI, Alfonso P, et al. Modeling transmission of avian influenza viruses at the human-animal-environment interface in Cuba. Front Vet Sci. 2024;11:1415559.,5454. Montano Valle D de las N, García OL, Hernandez BD, Abreu MIP, Pérez DQ, Silva LC, et al. Toward a One Health Surveillance System in Cuba: Co-Productive Stakeholder Engagement. One Heal Cases. 2023;ohcs20230024.).

Conclusions

These current results provide a novel contribution to early planning of AIV surveillance in migratory wild birds based on the influence of seasonal fluctuations of prevalence-weighted abundance and frequency that may strengthen detectability of AIVs targeting most suitable species and locations. Blue-Winged Teal was markedly the foremost ranked species, for Cuba, while “Los Palacios” and “Ciénaga de Zapata” were predicted as most appropriate locations during fall migration. The prospectively deduced risk index could provide predictions about AIV circulation in each species and location, but would also offers a novel insight for understanding the wild bird-poultry interface in Cuba. The prospect of poultry production management avoiding its growth in proximity to identified risky areas was an ancillary benefit even from a conservationist perspective, considering the bidirectional transfer of pathogens between the wild bird-poultry interface.