Immunising Pets in Southeast Asia

Immunisation of companion animals not only preserves the health of animal populations, but have broader implications on human and population health.

Southeast Asia’s tropical climate encourages the spread of many pathogens, complicating disease control efforts in humans and their animal companions.

In line with the One Health approach, the World Organisation for Animal Health (WOAH), formerly known as OIE, emphasises immunisation as a key component of responsible pet ownership and disease control, highlighting the interconnectedness between animal, human and environment health.

Infectious diseases in pets

Based on the Consumer Report Malaysia 2023, 51.1% of Malaysians have at least one pet. About 70% of Thais own pets, while only 33% of Singaporeans are pet owners, although the pet population on the island has increased by almost 3% and 4%, for dogs and cats respectively, since 2019.

Companion animals such as cats and dogs can transmit various infectious diseases to humans, through a process known as zoonosis, either through direct contact, bites and scratches from the animal, or indirectly through fleas or ticks. These infectious diseases continue to be prevalent where vaccination is low:

In cats:

1.      Feline Panleukopenia (Feline Parvovirus) is highly contagious and often fatal, especially in kittens.

2.      Feline Calicivirus (FCV) and Feline Herpesvirus (FHV) is responsible for upper respiratory infections that can spread easily, especially in multi-cat environments.

3.      Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) compromise immune function and predispose cats to secondary infections.

4.      Rabies is less common in cats compared to dogs, but still poses a risk in stray populations.

In dogs:

1.      Rabies causes approximately 59,000 human deaths annually worldwide, with most deaths occurring in Asia, according to the World Health Organization (WHO).

2.      Canine Parvovirus (CPV) causes severe gastrointestinal illness in puppies and unvaccinated dogs.

3.      Canine Distemper Virus (CDV) affects multiple organ systems, potentially causing death

4.      Canine Adenovirus (CAV), is responsible for infectious hepatitis and respiratory disease.

The spread of rabies has been escalating in Southeast Asia since 2020, with high mortality rates which impact both human and animal lives. According to a white paper titled, ‘Moving towards a rabies-free Southeast Asia’ by Global Alliance of Rabies Control (GARC) and Boehringer Ingelheim, factors contributing to this increase include large free-roaming unvaccinated dog populations, resource diversion due to COVID-19 and competing diseases, difficulty in accessing vaccines and medical treatments, and sociocultural influences on rabies perception.

Thailand

Rabies remains a serious public health concern in Thailand, particularly in urban areas such as Bangkok due to stray dog populations. According to the Livestock Development Department, the number of stray cats and dogs is expected to hit 2 million by 2027, an increase from 820,000 in 2017.

Dr Ratanaporn Tangwangvivat (Katai), Senior Veterinary Technician, Singapore

“Domestic animals such as dogs and cats pose the highest risk of transmitting rabies to humans. There are also reports of infected dogs biting cattle, leading to the cattle becoming infected. Humans who handle or slaughter infected cattle are also at risk of contracting rabies,” explains Dr Ratanaporn Tangwangvivat (Katai), Senior Veterinary Technician currently based in Singapore. She previously practiced as a veterinary doctor in Bangkok.

In response to the recent rabies outbreak in Soi Onnut 86, the Bangkok Metropolitan Administration has initiated a ring vaccination campaign within a 5-kilometer radius of the outbreak. Mass dog vaccination drives have been instrumental in reducing human rabies incidence over the year. There were only four reported cases in 2012 compared to the 370 human rabies cases in 1980.

“In Thailand, annual rabies vaccinations are recommended, with the government implementing large-scale rabies vaccination programmes. However, low vaccination coverage, issues with maintaining the vaccine cold chain, and overpopulation of stray animals contribute to the limited success of these efforts,” adds Dr Katai.

Malaysia

In Malaysia, Sarawak has been the most affected by rabies, accounting for 97.99% of cases from 2015 to 2023. The state has been battling a rabies outbreak since 2017, which has to date resulted in 83 human rabies cases and 76 fatalities, according to the Sarawak State Health Department. The human rabies case fatality rate has increased to 90.28%, emphasising the need for urgent public health action.

Dr Lee Ee Liang, Practice Director, Vet Partners Veterinary Clinic, Johor

Says Dr Lee Ee Liang, Practice Director, Vet Partners Veterinary Clinic in Johor, “Rabies is not only a threat to stray animals or those near wildlife populations; companion animals can also come into contact with a rabid animal."

"In 2017, a pet dog in Perak contracted the virus from rabid dogs brought into the country by boat, and subsequently infected two children. This underscores the importance of vaccinating pets against rabies, even if they are strictly indoor animals residing in big cities. Increasing vaccination rates among pets and promoting herd immunity is the only effective way to eradicate this deadly disease,” explains Dr Lee.

Anti-rabies vaccinations has been made compulsory to all pet dogs in Sarawak since 2025. While the vaccination is not compulsory in Peninsular Malaysia, it is compulsory to vaccinate dogs which live within 50 to 80km from the Thai border, also known as the ‘immune belt’. 

Singapore

Rabies has been successfully eradicated in Singapore since 1952, due to its stringent import controls, strict animal control policies, high vaccination coverage and stray management initiatives. High vaccination coverage has led to a low incidence of core diseases, including rabies, although sporadic outbreaks do occur, often from imported animals and expatriate communities, which contribute to the need for ongoing surveillance.

“Despite strict government policies and mandatory vaccinations for pets, there are still some challenges. For example, some pet owners believe a single vaccination is sufficient for the pet’s entire lifespan, or that it is not necessary to see a doctor to get vaccinated after being bitten by a stray animal. Some pet owners are also not aware their animals need to be vaccinated, or the vaccines may be unavailable at certain times of the year due to high demand,” says Dr Katai.

Immunisation in disease control

“All core vaccines recommended by the WSAVA, are essential for all companion animals regardless of geographic location, lifestyle or breed as they protect against severe, life-threatening diseases with global distribution,” states Dr Katai.

Dr. Lim May Lyn, Clinical Director, Pet Wellness Veterinary Clinic, Penang

“Just like humans, cats and dogs need protection from various diseases. Vaccinating household pets not only protects them from highly contagious and/or life-threatening diseases, but also contributes to a healthier community for all animals,” says Dr. Lim May Lyn, Clinical Director, Pet Wellness Veterinary Clinic, Penang. "It also lowers or eliminates veterinary costs and the emotional distress related to pet illness or death. Ultimately, vaccination enhances animal welfare by promoting longer, healthier lives."

“Even indoor cats and dogs must be vaccinated, as they can be exposed to pathogens when they are taken out of the house to public places such as parks, pet hotels, and pet grooming salons, and when they gather or meet with other animals.”

Dr Lim recommends, “Pets should receive their initial dose of core vaccinations as puppies or kittens between six to eight weeks of age, with booster shots every two to four weeks until around 16 weeks old, followed by annual booster shots, in line with the latest World Small Animal Veterinary Association (WSAVA) Vaccination Guidelines. The exact schedule should be determined by the veterinarian based on each pet's lifestyle and the prevalence of local diseases.”

Broader implications on One Health

Immunisation of companion animals has broader implications on One Health. As human populations grow and expand into new geographic areas, more people are living in close contact with wildlife and domesticated animals, both livestock and pets. Close contact with animals and their habitats provide more opportunities for diseases to transmit between animals and people. With international travel and trade, diseases can now spread quickly across borders, as was witnessed with the COVID-19 pandemic.

In recent years, Southeast Asian countries have observed a promising trend towards increased pet vaccination, fuelled by large-scale public awareness campaigns, supportive government policies and veterinary outreach programmes. These strategic initiatives, along with the increasing occurrence of zoonotic diseases and infectious disease outbreaks in the region, have spurred the urgency of vaccination drives throughout the region.

Countries such as Indonesia, the Philippines, Thailand and Vietnam have established national rabies control programmes which incorporate mass dog vaccination drives, funded by international organisations like WHO. In Malaysia there are nationwide programmes such as ‘Rabies-Free Malaysia’ which aims for 80% vaccination coverage among dogs by 2025, while the ‘Disease-free Animals, Save Humans from Rabies’ project launched in 2023 by Professor Dr. Her Royal Highness Princess Chulabhorn Mahidol, aims for Thailand to achieve rabies-free status by 2030, in line with WHO’s goals.

However, more sustainable solutions are required. Rabies is still considered a neglected zoonotic disease under the list of neglected tropical diseases (NTD). Global and national stakeholders lack awareness about the importance of the disease and have not made it into a public health priority, and global funding agencies such as the World Bank typically do not provide funding for rabies elimination efforts. This has led to rabies being under-resourced especially in the areas most affected by the disease.

To enhance immunisation rates among companion animals in the region, several strategies can be considered. Public education through community outreach and media campaigns can raise awareness about the importance of pet vaccination, while vaccine coverage gaps can be narrowed by improving access through subsidised vaccination services and mobile clinics, particularly in rural areas.

Effective stray animal management, including widespread sterilisation and vaccination programmes like Singapore’s ‘Trap-Neuter-Release/Rehome’ (TNR) initiative, is also critical, alongside enforcing compulsory vaccination laws and pet registration. Ongoing research and surveillance to monitor disease trends and vaccine efficacy will also support the development of more robust animal health policies.

Ultimately, strengthening immunisation efforts for companion animals, involves better cooperation and coordination from various stakeholders, including government agencies, pharmaceutical companies and vaccine manufacturers, as well as animal and environmental advocacy groups.