The High Price of Parasites: What’s at Stake for Farmers and Food Security

In recognition of World Parasite Awareness Day 2025, this blog explores how parasitic infections weaken animals, reduce farm productivity, threaten food security, and increase zoonotic disease risks. By applying a One Health approach, VWB is empowering communities with the knowledge and tools to prevent and manage parasites—protecting farmers, strengthening food systems, and building resilient communities. Written by Tanja Kisslinger, Advocacy and Communications Technical Advisor, VWB.

An Overlooked Crisis in Animal Health

Parasites are among the most widespread yet underestimated threats to livestock health and productivity. While many farmers recognize external parasites like ticks and mites, the impact of internal parasites such as gastrointestinal worms and liver flukes often goes unnoticed—until production losses become severe.

For smallholder farmers, livestock represent a lifeline—providing food, income, and agricultural labor. Yet, parasite infestations silently erode animal health, reduce productivity, and increase veterinary costs, creating a cycle of financial hardship. The issue is not just economic; parasites also contribute to malnutrition, food insecurity, and zoonotic disease risks, particularly in vulnerable rural communities.

A One Health approach—which recognizes the interconnectedness of animal, human, and environmental health—is essential to breaking this cycle. Understanding the hidden cost of parasites and taking proactive, sustainable action can protect livelihoods and improve food security worldwide.

PHOTO: Ho Penh, a farmer in rural Cambodia, gained holistic training in livestock health, sustainable agriculture, One Health, and gender equality through VWB's AGROW.

The Economic Toll: How Parasites Drain Farmers' Livelihoods

Parasites impose significant financial burdens on livestock farmers, particularly those in low- and middle-income countries where access to veterinary care is limited. These economic losses occur in several ways:

• Reduced Productivity: Infected animals experience decreased milk production, slower weight gain, and lower fertility rates. Studies show that parasitic infections in dairy cows can reduce milk yield by up to 15-20%, with even greater losses in untreated animals.
• Increased Veterinary Costs: Parasite-ridden animals require more frequent medical interventions, deworming treatments, and nutritional support, raising expenses for farmers who may already struggle with limited resources.
• Livestock Mortality & Market Losses: In severe cases, parasites can cause direct fatalities or render animals unsuitable for sale due to weight loss, poor body condition, or contamination concerns (e.g., liver flukes making livers unfit for consumption).

A global study on the economic impact of parasitic infections in livestock estimates that losses related to cattle alone amount to billions of dollars annually, impacting both individual farmers and national economies. 

The Human Cost: Malnutrition, Food Insecurity, and Zoonotic Risks

Livestock play a critical role in ensuring food security, particularly for smallholder farmers who rely on animal products for daily nutrition. When parasites weaken animals, the effects cascade to human populations:

• Malnutrition & Protein Deficiency: Reduced milk, meat, and egg production translates into lower protein intake for families, increasing the risk of malnutrition, especially in children and pregnant women.
• Zoonotic Disease Risks: Many livestock parasites can also infect humans, causing diseases such as cysticercosis (pork tapeworm), echinococcosis (hydatid disease), and toxoplasmosis. These diseases are prevalent in regions where parasite control measures are inadequate.
• Economic Hardship & Migration: Families experiencing repeated livestock losses may sell off animals prematurely, take on debt, or migrate in search of better opportunities, exacerbating rural poverty.

In many low-income settings, women and children bear the brunt of these effects, as they are often responsible for livestock care and household nutrition. Protecting livestock health is essential to protecting human health.

PHOTO: A mother and small-scale farmer in Aweil East, South Sudan, attending a mass livestock vaccination campaign by VWB and partners in September 2024.

The One Health Connection: Why Managing Parasites Matters for People and the Environment

Effective parasite management goes beyond veterinary care—it benefits entire ecosystems and communities. The One Health approach highlights how parasite control in livestock improves environmental sustainability, human well-being, and economic resilience.

• Environmental Impact: Overuse of chemical dewormers contributes to anthelmintic resistance and contaminates soil and water sources, harming beneficial organisms. Sustainable parasite control methods, such as rotational grazing and targeted deworming, help protect biodiversity.
• Public Health Protection: By reducing parasite loads in animals, the risk of zoonotic disease transmission to humans decreases, especially in rural areas where people and livestock live in close contact.
• Stronger Rural Economies: Healthier livestock mean higher productivity, improved market value, and greater economic stability for farming households.
  

Addressing parasite infestations through integrated, science-based solutions ensures long-term benefits for both human and animal populations.

VWB in Action: The COHERS Program in Rwanda and Senegal

Veterinarians Without Borders (VWB) is addressing the challenge of parasites in livestock through Community One Health Empowerment in Rwanda and Senegal (COHERS). This initiative recognizes the deep connections between human, animal, and environmental health and is working to empower communities with the tools to prevent, detect, and respond to zoonotic diseases, including parasite-related illnesses.

Specifically, COHERS operates in Nyamagabe District in Rwanda and Kedougou and Velingara Departments in Senegal, where high human-animal-environment interaction increases the risk of zoonotic disease transmission. The program specifically targets marginalized groups, particularly women and girls, who are often responsible for household livestock care, water sanitation, and food preparation—roles that increase their exposure to parasitic diseases such as anthrax and cysticercosis.

PHOTO: In Rwanda, Dr. Cate Dewey (University of Guelph) assesses a pig’s health while training a COHERS farmer, alongside University of Global Health Equity representatives..

Key COHERS program activities to combat livestock parasites include:

• Training & Capacity Building: COHERS is establishing and training One Health Teams (OHTs), consisting of Community Health Workers (CHWs), Community Animal Health Workers (CAHWs), and Water, Sanitation, and Hygiene (WASH) specialists. These teams help identify, prevent, and manage parasite-related health issues at the local level.
• Gender-Responsive Approaches: The program ensures that women and girls play a leading role in zoonotic disease control, empowering them with knowledge and decision-making power in animal health, household sanitation, and water management.
• Community Outreach & Sensitization: Through One Health Days, workshops, and educational campaigns, COHERS is improving awareness of human-animal-environment interactions and the importance of parasite control.
• Resource Provision: The program is supplying vaccines, diagnostic tools, and treatment medications to support parasite prevention and control in livestock.
• Collaborative Research & Policy Advocacy: In partnership with local and international organizations, COHERS is generating evidence-based solutions to inform better national policies on One Health strategies and livestock health management.

Through these targeted interventions, COHERS aims to directly reach over 127,674 people by 2027, strengthening the resilience of smallholder farmers and their communities against the burden of parasites.

A Call to Action for Sustainable Parasite Control

Parasites are often unseen, but their consequences are undeniable—weakening livestock, reducing food production, and keeping families trapped in cycles of economic hardship. The stakes are highest for smallholder farmers, who depend on their animals for nutrition, income, and resilience against climate and market fluctuations. Without action, parasites will continue to silently erode livelihoods and food security.

What is needed?

• Scalable, cost-effective parasite management solutions that work for smallholder farmers, not just industrial agriculture.
• Stronger veterinary outreach and training programs to equip communities with the knowledge and tools to prevent infestations before they cause irreparable damage.
• Greater commitment to One Health principles, recognizing that protecting animal health is fundamental to human well-being and environmental stability.

The cost of prevention is far lower than the cost of inaction. By investing in parasite control today, we can help farmers build healthier herds, strengthen food systems, and create more resilient communities worldwide.

PHOTO: In Ghana, VETS-trained Community Animal Health Workers Clement Afuo (L) and Ida Achatowe (C) use the FAO mobile app to help a farmer (R) report her goat's symptoms.

Learn More

To learn more about parasite prevention in livestock and its impact on food security and One Health, see:

• Food and Agriculture Organization (FAO) – The economic impact of parasitic diseases on livestock and global efforts to improve animal health.
• World Health Organization (WHO) – Zoonotic parasites and their role in human and animal health, plus global strategies for disease control.
• Centers for Disease Control and Prevention (CDC) – Neglected parasitic diseases and their public health significance worldwide.
• World Organisation for Animal Health (WOAH) – Guidelines on parasite control in livestock and sustainable animal health practices.
• The Lancet Global Health – Research on emerging parasitic diseases, One Health interventions, and the impact of parasites on global food systems.