Tick Bornes Diseases

 

As human and commercial traffic intensifies, we are inadvertently facilitating the spread of diseases and parasites that threaten the very stability of regional agriculture. Organizations like CIRAD and the ASTRE (Animal, Santé, Territoires, Risques et Écosystèmes) research unit are monitoring, detecting, and preventing animal diseases, especially those that can: Spread across borders, Affect food production and livelihoods and Pose risks to human health. In her talk Dr M.Dupraz gave an over of the current tick borne diseases in the region.

1. A 19th-Century Legacy of Uninvited Guests

The tick crisis in the Indian Ocean is not a modern phenomenon but a persistent biological debt incurred during the height of colonial commerce. These parasites were originally introduced alongside ruminant imports from East and South Africa during the 19th century, with subsequent introductions arriving from Asia. This historical context reveals a profound irony: the same trade routes that built the region’s modern economy also imported a permanent ecological challenge.

"Dynamic region: high human and commercial traffic... Ticks imported with their ruminant hosts from East and South Africa in the 19th century, then from Asia."

This legacy reminds us that human "progress" often carries unintended biological baggage. By moving animals across oceans without modern biosecurity, we created a permanent shift in the regional ecosystem that farmers are still paying for over a century later.

2. Beyond the Bite: The Massive Economic Toll

A tick infestation is far more than a simple veterinary nuisance; it is a systemic drain on the region's prosperity. The damage is felt in two distinct waves that compromise both animal welfare and provincial food security.

Direct Impacts on Animal Health

• Massive Blood Loss: Severe infestations lead to debilitating anemia and physical exhaustion.
• Physical Trauma: Ticks cause painful abscesses and opportunistic skin diseases at the site of attachment.

Indirect Impacts and Economic Destabilization

• Pathogen Transmission: Ticks serve as high-speed vectors for lethal bacteria and protozoa.
• Production Decline: There is a sharp drop in growth rates and milk yields, directly threatening the food security of island populations.
• Rising Costs: Smallholders face a mounting financial burden from veterinary fees and the purchasing of acaricides like Butox, often with diminishing returns.

3. A Rogues' Gallery of Deadly Pathogens

 

The ticks of the Indian Ocean are efficient biological delivery systems. Understanding the specific pathogens they carry is vital for "One Health" monitoring, as the windows for intervention are often incredibly narrow. The speed of mortality—sometimes as little as 24 hours after symptoms appear—makes these "tiny travelers" some of the most dangerous inhabitants of the islands.

Tick Species	Pathogen & Disease	Symptoms & Incubation	Treatment Outlook
Amblyomma variegatum	Ehrlichia ruminantium (Cowdriosis)	Sudden fever, nervous symptoms (stiffness, trembling). Incubation: 2–3 weeks.	Mortality in 1–6 days; requires urgent Tetracycline injection.
Rhipicephalus microplus	Babesia bovis/bigemina (Babesiosis) & Anaplasma marginale (Anaplasmosis)	High fever, jaundice, dark urine, anemia. Incubation: 1–4 weeks.	Treated with Imidocarb or Oxytetracycline; vaccines available.
Rhipicephalus evertsi	Nairobi sheep virus & Theileria parva (Theileriosis)	Hemorrhagic gastroenteritis, abortion, fever, lethargy. Incubation: 2–21 days.	Nairobi virus: No specific treatment. Theileriosis: Buparvaquone/Oxytetracycline.

4. The "Super-Tick" and the Failure of Chemical Warfare

For decades, the "Lutte chimique" (chemical control) has been the frontline defense. However, we have reached a dangerous tipping point. The species Rhipicephalus microplus has evolved into a "super-tick," showing widespread acaricide resistance. This crisis is exacerbated by a diminishing number of available active ingredients; as the molecules themselves become obsolete, the chemical "arms race" is being lost.

Currently, while products like Butox remain in use, the source context reveals a management void: Lutte génétique (genetic control) is currently "non appliquée" (not applied), and authorized vaccines are frequently unavailable. This over-reliance on a single, failing solution has only made the pests stronger. To combat this, we must pivot toward "Integrated Management." This includes difficult but necessary agronomic shifts such as:

• Gyrobroyage: Mechanical brush clearing to destroy tick habitats.
• Movement Monitoring: Strict tracking of animal transit to isolate infested zones.
• Targeted Treatments: Moving away from blanket spraying toward strategic, data-driven applications.

Conclusion: The Road Toward Integrated Resilience

The future of the region depends on moving beyond the sprayer. Under the umbrella of the "One Health OI" partnership, researchers like Marlène Dupraz are developing a multi-pillar approach to resilience. By combining the inventory and mapping of species with molecular diagnosis and risk assessment, the goal is to create "Integrated control plans" that respect the link between the animal, the environment, and the human economy.

As we continue to enjoy the benefits of global connectivity, we must confront a difficult question: how can we balance the high-speed demands of international trade with the absolute necessity of local biological security?