Ewaldus Wera

Objective: This study aimed to investigate morphometric and plumage-colour variation among native chickens from Wallacea and Java, Indonesia, and to evaluate the contributions of geographic and production-system factors to phenotypic diversity. Methods: Native chickens were sampled from 259 households across eight provinces in Indonesia. Household-level information on production systems and farmer selection practices was collected through structured surveys. Morphometric traits and HSV-derived plumage-colour variables were analysed using principal component analysis (PCA), permutational multivariate analysis of variance (PERMANOVA), and hierarchical variance partitioning to assess phenotypic variation across locations, provinces, and islands. Results: Substantial phenotypic variation was observed among sampled populations, with significant province- and island-level differences detected for several morphometric traits. However, extensive overlap among locations was evident in both morphometric and plumage-colour space, indicating diffuse rather than discrete structuring. Within-location variation accounted for the largest proportion of total phenotypic variance across most traits, consistent with decentralised smallholder management and continued human-mediated exchange. Conclusion: Geographic fragmentation and agroecological heterogeneity alone appear insufficient to generate strongly differentiated phenotypic groups when connectivity among populations is maintained. Whether this phenotypic connectivity corresponds to contemporary gene flow, retained ancestral variation, or convergent environmental responses remains to be tested using genomic data.

This study evaluated the husbandry and management practices adopted by the pig farmers and the potential of African Swine Fever (ASF) in Kupang, East Nusa Tenggara, Indonesia. Husbandry and management practices evaluated include educational background, main occupation, livestock pens, animal feed and drinking water systems, reproductive management, and pig body condition. Data were collected from 300 pig farmers using interviews and questionnaires. This study was conducted in the districts of Kupang Timor and Amabi Oefeto from June to October 2022. This study reported several factors that could potentially affect the ASF transmission. These practices can be improved to prevent the potential of ASF transmission. The educational background of pig farmers, primary occupation, caging management, swill feeding, and reproductive management may have potentially contributed to the ASF transmission in Kupang during the outbreak period.

Wilayah pantai Timor Barat memiliki banyak pelabuhan tradisional dan merupakan daerah transit nelayan dari dan keluar pulau Timor. Penularan rabies melalui pelabuhan tradisional sangat mungkin terjadi sehingga menempatkan Timor Barat pada kategori daerah beresiko tinggi tertular rabies di masa yang akan datang. Ketersediaan data demografi dan kepadatan populasi anjing di wilayah pantai Timor Barat sangat penting dalam pengendalian rabies yang efektif dan efisien jika terjadi wabah. Tujuan penelitian ini adalah untuk menggumpulkan data demografi dan mengestimasi kepadatan populasi anjing di wilayah pantai Timor Barat. Survei telah dilakukan pada bulan Juni-Agustus 2021. Hasil penelitian menunjukan bahwa kepadatan populasi anjing di wilayah pantai Timor Barat berkisar antara 98-333 ekor per km2 dan didominasi oleh anjing berjenis kelamin jantan (62%), berumur lebih dari satu tahun dengan skor kondisi tubuh sedang. Jumlah jantan yang dominan berpotensi mempercepat laju penularan penyakit jika terjadi wabah penyakit zoonosis seperti rabies. Hal ini cukup beralasan karena daya jelajah anjing jantan jauh lebih luas dibanding anjing betina. Keberadaan anjing umur lebih dari satu tahun dan bebas berkeliaran di area umum akan berpotensi meningkatnya laju pertumbuhan populasi anjing mengingat kelompik anjing ini akan bereporoduksi tanpa terkendali. Untuk itu edukasi manajemnen pemeliharaan dan kesehatan anjing perlu dilakukan untuk menekan laju pertumbuhan populasi.

Vaccination is the main tool to prevent the circulation of rabies in dog populations. The development of an immune response after vaccination differs between individual dogs and depends on many factors such as dog characteristics, management, or genetics. Here, we first investigated the level of, and associated factors for, the presence of binding antibodies in 130 healthy dogs from Flores Island, Indonesia. Secondly, we identified factors associated with the development of binding antibodies within 30 days after vaccination among a subsample of dogs that had a binding antibody titre N = 91). Blood samples were collected from the individual dogs immediately before vaccination at D0 and 30 days after vaccination (D30). The rabies antibody titres were determined using ELISAs. Information on potential risk factors such as the dog's age and sex, history of vaccination, type and frequency of feeding, and BCS (body condition score) were gathered during interviews at D0. Regression analyses were performed to identify the risk factors associated with the presence of binding antibody titre ≥0.5 EU/ml at D0 for the 130 dogs and the development of binding antibody titre ≥0.5EU/ml at D30 for the 91 dogs. The results showed that the proportion of dogs with antibody titre ≥0.5 EU/ml was 30% (39/130) at D0. The only factors found to be significantly influencing the presence of binding antibodies titres ≥0.5 EU/ml was previous vaccination within 1 year before D0 [46.8 vs. 14.7%, Odds ratio (OR) = 3.6, 95%CI 1.5–9.3; p-value = 0.006], although the same trend was found for dogs of higher age and better BCS. Eighty-six percent (79/91) of dogs whose rabies binding antibody level was p-value = 0.057. Twelve (13.2%) dogs retain binding antibody level <0.5 EU/ml at D30, indicating poor immune response after vaccination. A majority of them did not receive vaccine before D0 according to the owner and had poor BCS (83.3%; 10/12). Our findings show the high effectiveness of rabies vaccine in under field conditions to develop measurable immunity and the importance of a good BCS, often achievable by good dog keeping conditions, for developing efficient immunity after parenteral vaccination in dogs.

Effective parenteral vaccines are available to control rabies in dogs. While such vaccines are successfully used worldwide, the period between vaccine boosters required to guarantee protection of the population against rabies varies between vaccines and populations. In Flores Island, Indonesia, internationally and locally produced rabies vaccines are used during annual vaccination campaigns of predominantly free-roaming owned domestic dogs. The study objective was to identify the duration of the presence and factors associated with the loss of adequate level of binding antibodies (≥0.5 EU/ml) following rabies vaccination in a domestic dog population on Flores Island. A total of 171 dogs that developed an antibody titre higher or equal to 0.5 EU/ml 30 days after vaccination (D30), were repeatedly sampled at day 90, 180, 270, and 360 after vaccination. On the day of vaccination (D0), an interview was performed with dog owners to collect information on dog characteristics (age, sex, body condition score (BCS)), history of rabies vaccination, kind of daily food, frequency of feeding, and origin of the dog. Serum samples were collected and the level of antibodies was quantitatively assessed using ELISA tests. Dogs were categorized as having an adequate level of binding antibodies (≥0.5 EU/ml) or inadequate level of binding antibodies (<0.5 EU/ml) at each time points examined. A total of 115, 72, 23, and 31 dogs were sampled at D90, D180, D270, and D360, respectively, with the highest proportion of antibodies ≥ 0.5 EU/ml (58%, 95% CI, 49–67%) at D90, which reduced gradually until D360 (35%, 95% CI, 19–52%). Multivariable logistic regression models showed that loss of adequate level of binding antibodies is significantly associated with dogs having no history of vaccination or vaccination applied more than 12 months before D0, being less than 12 months of age, and having a poor BCS. These results highlight the importance of BCS regarding the immune response duration and provide insights into frequency of vaccination campaigns required for the internationally available vaccine used on Flores Island. For dogs without vaccination history or vaccination being applied more than 12 months before D0, a booster is recommended within 3 months (a largest drop of antibodies was detected within the first 90 days) after the first vaccination to guarantee measurable protection of the population that lasts at least for one year.

A dynamic deterministic simulation model was developed to determine the cost-effectiveness of different mass dog vaccination strategies against rabies in a dog population representative of a typical village on Flores Island. Cost-effectiveness was measured as public cost per averted dog-rabies case. Simulations started with the introduction of one infectious dog into a susceptible dog population of 399 dogs and subsequently ran for a period of 10 years. The base scenario represented a situation without any control intervention. Evaluated vaccination strategies were as follows: annual vaccination campaigns with short-acting vaccine (immunity duration of 52 weeks) (AV_52), annual campaigns with long-acting vaccine (immunity duration of 156 weeks) (AV_156), biannual campaigns with short-acting vaccine (BV_52) and once-in-2-years campaigns with long-acting vaccine (O2V_156). The effectiveness of the vaccination strategies was simulated for vaccination coverages of 50% and 70%. Cumulative results were reported for the 10-year simulation period. The base scenario resulted in three epidemic waves, with a total of 1274 dog-rabies cases. The public cost of applying AV_52 at a coverage of 50% was US$5342 for a village. This strategy was unfavourable compared to other strategies, as it was costly and ineffective in controlling the epidemic. The costs of AV_52 at a coverage of 70% and AV_156 at a coverage of 70% were, respectively, US$3646 and US$3716, equivalent to US$3.00 and US$3.17 per averted dog-rabies case. Increasing the coverage of AV_156 from 50% to 70% reduced the number of cases by 7% and reduced the cost by US$1452, resulting in a cost-effectiveness ratio of US$1.81 per averted dog-rabies case. This simulation model provides an effective tool to explore the public cost-effectiveness of mass dog vaccination strategies in Flores Island. Insights obtained from the simulation results are useful for animal health authorities to support decision-making in rabies-endemic areas, such as Flores Island.

Rabies has been a serious public health threat in Flores Island, Indonesia since it was introduced in 1997. To control the disease, annual dog vaccination campaigns have been implemented to vaccinate all dogs free of charge. Nevertheless, the uptake rate of the vaccination campaigns has been low. The objective of this paper is to identify risk factors associated with the uptake of rabies control measures by individual dog owners in Flores Island. A total of 450 dog owners from 44 randomly selected villages in the Sikka and Manggarai regencies were interviewed regarding their socio-demographic factors, knowledge of rabies, and their uptake of rabies control measures. The majority of dog owners surveyed (>90%) knew that rabies is a fatal disease and that it can be prevented. Moreover, 68% of the dog owners had a high level of knowledge about available rabies control measures. Fifty-two percent of the dog owners had had at least one of their dogs vaccinated during the 2012 vaccination campaign. Vaccination uptake was significantly higher for dog owners who resided in Sikka, kept female dogs for breeding, had an income of more than one million Rupiah, and had easy access to their village. The most important reasons not to join the vaccination campaign were lack of information about the vaccination campaign schedule (40%) and difficulty to catch the dog during the vaccination campaign (37%). Dog owners in Flores Island had a high level of knowledge of rabies and its control, but this was not associated with uptake of the 2012 vaccination campaign. Geographical accessibility was one of the important factors influencing the vaccination uptake among dog owners. Targeted distribution of information on vaccination schedules and methods to catch and restrain dogs in those villages with poor accessibility may increase vaccination uptake in the future. Rabies has been a serious public health threat in Flores Island since its introduction in 1997, with significant economic consequences for the government due to the cost of providing vaccines for humans and dogs. Vaccination of dogs against rabies offers a safe and effective means to prevent rabies in humans in the long term. The local government of Flores Island has implemented dog vaccination campaigns throughout the island, free of charge for all dog owners. However, the uptake rate of vaccinating dogs is too low to control the disease. Identifying factors associated with the dog owners’ decisions to vaccinate their dogs provides information to policy makers to increase vaccination uptake in the future. This study evaluated the impact of rabies knowledge and socio-demographic factors of dog owners on the uptake of the 2012 dog vaccination campaign. Overall, the uptake rate of the 2012 vaccination campaign was low. Levels of knowledge about rabies and its control were high, but not associated with uptake of vaccination. Geographical accessibility was significantly associated with vaccination uptake. Targeted distribution of information in those villages with poor accessibility may increase vaccination uptake in the future. Information should cover vaccination schedules and methods to restrain dogs.