IAS and diseases

Invasive alien species serve as vectors for existing diseases. These diseases can be transferred through wounds via toxins, allergens, stings, or bites. One of the most invasive mosquitoes, the Aedes albopictus (Asian tiger mosquito) in the world, is a vector for diseases like Dengue Fever and West Nile Virus. This is just a tip of the type of diseases that invasive species can spread.

Firstly, is the urva auropunctatus (Small Indian Mongoose), which is an invasive species that was first introduced into several oceanic islands with the sole purpose of controlling the rat and snake populations. It became too effective and began preying on other native species like reptiles and birds. It is a carrier for diseases like leptospirosis and rabies.

Leptospirosis is a zoonotic disease, found globally in water and soil. It can spread from animals to people. The symptoms of the disease are flu-like, but it can cause kidney or liver disease and is common in warm climates but occurs anywhere. Rabies, on the other hand, is a fatal viral disease that can spread to people and pets that are scratched or bitten by a rabid animal. It is also found in other wild animals like raccoons, bats, foxes, and skunks. In other countries, the most active carrier of rabies has been dogs. This disease targets the central nervous system, which may travel to the brain, resulting in death.

Secondly, the Amblyomma variegatum Fabricius (Tropical Bont Tick, Senegalese Tick) is an invasive species that causes heartwater in domestic animals. The bites from the ticks leave skin lesions, these lesions lead to acute dermatophilosis caused by the bacteria Dermatophilus congolensis, which is the main vector for Cowdria ruminantium, a microorganism that is the cause of heartwater. Heartwater in domestic animals costs the livestock industry an estimated US $47.6 million annually. The symptoms and signs of heartwater are unusable hides of poor quality, loss of milk production, weight loss, and sometimes death.

Thirdly, is the Achatina Fulica (Giant African Snail) which is native to East Africa and a tropical species. This hermaphrodite species can lay up to 1,200 eggs in a year. It is invasive and widely established throughout many islands in the Indo – Pacific, Caribbean, and southern and eastern Asia. It feeds on native crops and outcompeted other snails for food. It is a destructive and invasive species that is a vector for diseases such as meningitis through the parasitic rat lungworm. Meningitis is an infection that afflicts the brain and spinal cord. It has been known to affect babies, preschool children, and young people. Symptoms of this disease may include high fever, headache, a rash that doesn’t fade, sensitivity to bright lights, stiff neck, drowsiness, and seizures.

Lastly, is the Highly pathogenic avian influenza (HPAI) which is an economically and ecologically significant disease that affects domestic and wild birds throughout North America. Signs of this disease include lack of appetite, energy and coordination, nasal discharge, coughing, reduced egg production, misshapen or soft-shelled eggs, swelling in various parts of the body, purple discoloration, and diarrhea.

It is recommended that preventing the spread of invasive alien species and their disease must be met with caution. Subsequently, enhancing collaboration on IAS issues at the national and regional levels will help with communication. Communicating invasive alien species issues to the public through education may also reduce the impact of IAS. Read more recommendations in our policy brief ‘Invasive Species Threaten Livelihoods and Valuable Biodiversity in the Caribbean.’


USGS – Highly pathogenic avian influenza (HPAI): An emerging disease threat in North America

Policy Brief – Invasive Species Threaten Livelihoods and Valuable Biodiversity in the Caribbean

CaribbeanInvasives – IAS in the Caribbean

USDA – Human Health Impacts

American Veterinary Medical Association – Leptospirosis

Centers for Disease Control and Prevention – Rabies

World Health Organization – Meningitis