Asia-Pacific Biotech News

Fighting Unseen Invaders: Parasites, a Threat to Yours and Your Pet’s Health

Zoonotic diseases, transmitted from animals to humans, pose a significant threat to both animal and human health. With in-house pets being potential carriers due to parasites, how can we best curb the spread of such diseases?

by Prof Frederic Beugnet, Prof Rebecca Traub, Dr Malaika Watanabe, and Prof Piyanan Taweethavonsawat

It is probably fair to say that for many of us, the word “zoonosis” does not ring a bell. Zoonotic diseases are those diseases that are transmitted from animals to humans and have been an ongoing concern in recent years as they pose a threat to both animal and human health. For example, avian influenza has become endemic, with new emergent strains resulting in human deaths and disrupting poultry farming and supply every year. Nature is full of relationships, perhaps none as foundational as the one between humans and animals. Over the course of the millennia, animals and humans have built a special bond. We interact with them daily, and our health is interconnected. Thus, it is important to be aware of zoonoses and the actions that should be taken to prevent the spread of these zoonotic diseases.

Contrary to popular belief that zoonotic diseases only affect livestock or wild animals, in-house pets can also be reservoirs of infections, with parasites being the most common threat. In Southeast Asia, recent studies conducted by Boehringer Ingelheim Animal Health found that approximately 47% of dogs and 43% of cats were infected by parasites.1 These numbers are likely to rise with worsening climate change, urbanisation, and globalisation in the region. Considering that many pets are now kept indoors, living in close proximity to their owners, it is essential to preserve the health of pets to maintain the health of humans too. With how easily diseases can be transmitted across borders, the combined limited knowledge of parasitology and pet owners’ neglect of disease prevention can also easily compound and affect people on a global scale.

At the recent Asia Pacific Symposium on Parasitology and Vector-Borne Diseases hosted by Boehringer Ingelheim, leading parasitology researchers across ASEAN, Australia, China, and Japan shared the latest on various parasitic and vector-borne diseases affecting animals and humans. While there is a need to co-create effective disease-control strategies, a scarcity of research into the prevalence and impact of these parasites across the Asian subcontinent remains, holding back efforts to do so.

It was clear that these gaps in research and study needed to be addressed, and doing so would require more collaboration and insight sharing among regional scientific and health institutions.


Common Parasites in Asia

In the spotlight and centre of conversations at the symposium were hookworms and roundworms, as well as diseases spread by ticks and fleas. Several studies have revealed that hookworms, particularly the species Ancylostoma ceylanicum, are the most common parasites found in pet cats and dogs in the region.2 The emergence of A. ceylanicum in several countries, notably Cambodia, Myanmar, Thailand, and the Philippines, is particularly concerning as this bloodfeeding hookworm commonly infects humans through the skin, resulting in itchy skin rashes followed by abdominal pain and diarrhoea, and in heavy infections, weakness due to anaemia.3

Another species of hookworm, Ancylostoma braziliense, also commonly infects dogs and cats in Malaysia, Indonesia, Thailand, Cambodia, and northern Australia.2 Once infected, humans suffer prolonged cutaneous larva migrans, a severely itchy creeping dermatitis that can last for months or years if left untreated.4 These risks emphasise the need for improved diagnostics and a One Health approach to controlling these parasites, which includes deworming programmes for both humans and their pets.1

Given the high prevalence of these hookworms in household pets, it is crucial to ensure that pets are dewormed monthly to safeguard pet health, as well as family and community health.

Eyeworms have the potential to cause ocular larva migrans, while others can cause lymphatic filariasis, the leading cause of permanent disability worldwide.4 Eyeworms can be contracted from dogs and cats and cause permanent eye damage and even blindness in humans if transmitted. Lymphatic filariasis is an infection of the lymphatic system and can lead to abnormal enlargement of body parts, causing pain, severe disability, and social stigma. Furthermore, in cases of lymphatic filariasis, the demise of filarial worms and, notably, the liberation of Wolbachia bacteria had a significant impact on the patients’ inflammatory immune response.

Heartworm disease is a serious condition that causes severe lung pathology and may lead to heart failure, organ damage, and death in dogs.5 It is caused by a filariid, and mosquitoes are the vectors. Studies6 have shown that dogs are the preferred host and can be reservoirs of infection, posing a threat to naïve dogs and cats. Hence, pet owners must stay vigilant and take their pets to the vet immediately if they notice any of these signs. At the same time, it is imperative that dog owners practise regular heartworm prevention to protect their dogs from this potentially fatal disease. A rare occurrence of heartworm migration to the distal end of the femoral artery resulted in necrosis of the hind limb. Managing this condition proved challenging, emphasising the importance of prevention as the most effective approach.7

In regions with tropical climates, such as Southeast Asia, there is a high occurrence of canine vector-borne diseases.8 The three most common tick-borne diseases, Ehrlichiosis, Babesiosis, and Anaplasmosis, are transmitted by the brown dog tick, the most widely distributed tick in Asia, as identified in a Boehringer Ingelheim study.9 In particular, the bacteria responsible for causing Ehrlichiosis is found in numerous pet dogs from Southeast Asia,10,11,12,13 and the most common symptoms in dogs are fever, anorexia, lethargy, lymphadenopathy, and epistaxis.14 Dogs with Babesiosis also experience fever and anorexia, but will also have clinical signs associated with haemolytic anaemia including pale mucous membranes and sometimes jaundice. The abundance of these ticks in the environment and their potential to transmit life-threatening diseases are concerning and highlight the need for vigilance and timely intervention to prevent these diseases.


Prevention and Institutional Collaborations Are Key to Safeguarding Human and Animal Health

The real-life examples from each of the clinical studies shared at the symposium provided evidence that it is possible for pets to transmit diseases to their owners. Despite this, there are several effective preventive measures that can be taken to protect pet owners and their furry loved ones from these infections. One such method includes scheduling routine veterinary check-ups and regularly treating pets with monthly parasite prevention medicines, such as Boehringer Ingelheim’s NexGard Spectra and NexGard Combo, and Frontline anti-parasite medication.

Addressing these growing health concerns also requires an integrated, multi-stakeholder approach. Hence, collaboration is of utmost importance. Healthcare professionals and researchers must continue to work together to gather accurate and current data on parasites, identify emerging threats, track the effectiveness of control measures, and educate the community about the threats of parasites. The Asia-Pacific Symposium was fruitful in beginning these conversations, but more institutions must continue to support each other’s efforts to further scientific research on parasitology in the Asia-Pacific and develop effective disease-prevention solutions.

Additionally, an integrated approach involving local and international authorities would benefit resource-poor areas. Implementing educational and prevention programmes may help equip the public with necessary veterinary recommendations and reduce public exposure to zoonotic infections.

Through ongoing advancements, collaborative efforts, and a commitment to education and prevention, there can be a future where parasitic diseases pose minimal threats to both human and animal health. By remaining vigilant and making informed decisions, it is possible to create a world where parasites are effectively controlled, ensuring the wellbeing of all. [APBN]

This article was first published in the September & December 2023 print version of Asia-Pacific Biotech News.

About the Authors

Prof Frederic Beugnet, Head of Technical Services Pet Parasiticides for Boehringer Ingelheim







Prof Rebecca Traub, Professor in Veterinary Parasitology and Veterinary Biosciences







Dr Malaika Watanabe, Senior Veterinary Consultant at VEC Veterinary Clinic







Prof Piyanan Taweethavonsawat, Faculty of Veterinary Science (Parasitology unit), Chulalongkorn University