White-lipped peccary in the Amazon rainforest with Neospora caninum antibodies

Silent Threat: Unmasking a Hidden Disease in the Amazon's Wild Peccaries

Mira Elwood in Science & Nature August 2025 • 4 min read.

"Scientists uncover Neospora caninum antibodies in free-ranging white-lipped peccaries, shedding light on disease ecology and diagnostic challenges in wildlife."

The Amazon rainforest, a realm of unparalleled biodiversity, harbors secrets both wondrous and worrisome. Among these is the presence of diseases that can silently impact wildlife populations. White-lipped peccaries (Tayassu pecari), are social creatures roaming from Mexico to Argentina, play a pivotal role in the ecosystem and the local rural economy and are now facing a threat. As a game species, they are of economic significance for local rural economy but now face threat from parasitic diseases.

Neospora caninum, a coccidian parasite, initially recognized in dogs, has proven to infect a wide array of animal species. This parasite poses a threat to both domestic and wild animals, with canids serving as definitive hosts, and other animals including livestock are intermediate hosts, facing neurological and reproductive consequences. Understanding the dynamics of such infections in wild populations is crucial for effective conservation strategies.

In a recent study published in the Journal of Zoo and Wildlife Medicine, researchers delved into the serological landscape of free-ranging white-lipped peccaries in the Peruvian Amazon. Their focus: detecting antibodies specific to Neospora caninum, and further refining diagnostic methods suitable for wildlife species, in particular evaluating the effectiveness of using heterologous secondary antibodies in tests like the indirect fluorescent antibody test (IFAT).

Unveiling the Study: Methods and Key Findings

White-lipped peccary in the Amazon rainforest with Neospora caninum antibodies

The research team collected blood samples from 101 white-lipped peccaries across three conservation reserves in the Madre de Dios region of southeastern Peru. These samples were then subjected to rigorous testing to detect the presence of N. caninum antibodies. The diagnostic approach was multifaceted, involving:

Indirect Fluorescent Antibody Tests (IFAT): This involved using both collared peccary (Pecari tajacu) and swine (Sus scrofa domesticus) heterologous secondary antibodies to identify N. caninum antibodies. A cutoff of 1:50 was used to determine positive results, and positive samples were further titrated to quantify antibody levels.

Immunoblotting (IB): Samples were also analyzed using an immunoblotting test with an anti-swine conjugate to confirm the presence of antibodies.
Modified Agglutination Test (MAT): To ensure the anti-swine conjugate was viable, the researchers referenced results from previous MAT analyses for Toxoplasma gondii.
Comparative Analysis: The team compared the results of IFAT using both types of secondary antibodies with the immunoblotting results, using IB as the gold standard for accuracy.

The results revealed that 5 out of 101 peccaries (4.9%) tested positive for N. caninum across all three tests. An additional sample tested positive in both IFATs but was negative in the immunoblotting test. The team was able to determine:

Implications and Future Directions

This study marks the first report of N. caninum antibodies in free-ranging white-lipped peccaries, enhancing our understanding of the parasite's distribution and impact on wildlife. The successful use of swine and collared peccary conjugates as secondary antibodies opens doors for more accessible and cost-effective diagnostic testing in Tayassu species. Further research is needed to investigate the transmission pathways of N. caninum in the Amazon, assess the potential impact on peccary populations, and develop strategies to mitigate the risks to both wildlife and domestic animals. Understanding the interplay between disease, wildlife, and human activities is crucial for safeguarding the health of the Amazon ecosystem.

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Everything You Need To Know

What is Neospora caninum and why is it a concern for wildlife?

Neospora caninum is a coccidian parasite initially found in dogs but now known to infect many animals. It poses a significant threat to both wild and domestic animals. Canids are the definitive hosts, while other animals, including livestock, are intermediate hosts and can experience neurological and reproductive issues due to infection. Understanding how Neospora caninum spreads in wild populations is essential for creating effective conservation strategies. Further research should explore the specific transmission pathways within the Amazon and assess the overall impact on various animal populations. The absence of this research poses a challenge for predicting and mitigating potential outbreaks.

What methods were used to detect Neospora caninum antibodies in white-lipped peccaries, and why was it important to use multiple tests?

The study used several diagnostic methods to detect Neospora caninum antibodies in white-lipped peccaries. These methods included Indirect Fluorescent Antibody Tests (IFAT) using both collared peccary and swine heterologous secondary antibodies, immunoblotting (IB) with an anti-swine conjugate, and referencing previous Modified Agglutination Test (MAT) analyses for Toxoplasma gondii to ensure the viability of the anti-swine conjugate. By comparing the results from IFAT using both types of secondary antibodies with the immunoblotting results (using IB as the gold standard), the team was able to confirm the presence of Neospora caninum antibodies. However, it is important to note that the use of swine conjugates assumes similarity in antibody reactivity. If the epitopes recognized by swine antibodies differ significantly from those in peccaries, the test's sensitivity and specificity might be compromised, leading to false negatives or positives.

What percentage of the white-lipped peccaries tested positive for Neospora caninum antibodies, and what does this indicate about the parasite's prevalence?

The study found that 5 out of 101 white-lipped peccaries tested positive for Neospora caninum antibodies using IFAT and immunoblotting. Additionally, one sample tested positive in both IFATs but was negative in the immunoblotting test. This result highlights the challenges and importance of using multiple diagnostic tests to confirm the presence of Neospora caninum antibodies accurately. While a 4.9% positivity rate may seem relatively low, it does confirm the parasite's presence in the white-lipped peccary population, raising questions about its potential impact on the health and reproductive success of these vulnerable animals and the broader ecosystem.

What are the broad implications of finding Neospora caninum antibodies in Amazonian white-lipped peccaries for conservation and diagnostic practices?

The discovery of Neospora caninum antibodies in free-ranging white-lipped peccaries in the Peruvian Amazon has several implications. It indicates that the parasite is present in the ecosystem and can infect this species. The successful use of swine and collared peccary conjugates as secondary antibodies in IFAT suggests a more accessible and cost-effective method for diagnostic testing in Tayassu species. These findings also call for further research to understand the transmission pathways of Neospora caninum in the Amazon and assess the potential impact on peccary populations and other wildlife. Without deeper understanding, effective conservation strategies would be difficult.

What specific aspects of Neospora caninum infection in white-lipped peccaries were not covered in this study, and what further research could be beneficial?

The study primarily focused on detecting Neospora caninum antibodies in white-lipped peccaries through serological testing. While the study confirmed the presence of the parasite, it does not delve into the clinical signs or pathological effects of Neospora caninum infection in these animals. Further investigations could examine infected peccaries for neurological symptoms, reproductive issues, or other health problems to fully understand the impact of the parasite on their health and survival. Also, the study does not investigate the impact on local rural economy and the risk for human populations.