Illustration of farm animals under an ominous cloud representing Johne's disease.

Johne's Disease in Ruminants: What Farmers Need to Know About This Global Threat

Kai Mendoza in Health & Wellness December 2025 • 3 min read.

"A Comprehensive Guide to Paratuberculosis in Brazilian Livestock: Symptoms, Prevention, and Economic Impact"

Johne's disease, also known as paratuberculosis, poses a significant threat to livestock industries worldwide. This chronic, progressive disease primarily affects ruminants—cattle, sheep, goats, and buffalo—leading to substantial economic losses due to reduced productivity, premature culling, and increased veterinary costs. Understanding the complexities of Johne's disease is crucial for effective management and control.

The causative agent, Mycobacterium avium subspecies paratuberculosis (MAP), is a resilient bacterium that thrives within the intestinal cells of infected animals. Its ability to persist in the environment and evade the host's immune system makes it a formidable challenge for livestock producers. While the disease progresses slowly, often without visible symptoms in the early stages, the consequences can be devastating once clinical signs manifest.

In Brazil, paratuberculosis has been reported across various ruminant species and displays a broad geographic distribution. However, natural instances of the disease are underreported, and there is a belief that the commercialization of infected animals are responsible for interspecific transmission and agent dispersion. The need for effective sanitary policies and control measures for MAP within Brazil is imperative.

What are the Economic Repercussions of Johne's Disease on Farms?

Illustration of farm animals under an ominous cloud representing Johne's disease.

The economic impact of Johne's disease primarily hits dairy farms. Infections lead to a drop in milk production, slower weight gain, and poor breeding. Infected animals are often sold early or have less value when slaughtered.

The global economic impact is not fully known, but the losses in United States are estimated to be 250 million USD each year.

Reduced milk production
Decreased weight gain
Reproductive problems
Early culling
Lowered slaughter value

Besides direct economic losses, there's worry about MAP's possible role in Crohn's disease, a long-term digestive issue in humans. While this link is debated, studies show MAP is found in raw and pasteurized milk, and in the blood of Crohn's patients. This connection requires more research to determine MAP's primary role.

Protecting Livestock and Livelihoods from Johne's Disease

To improve animal product quality on international markets, there needs to be more implementation of sanitary controls in the country. To that end, research should be focused on the development of better diagnostic test. Molecular studies can then be used to evaluate and further the tests to look for different strains and control the disease.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1590/s0100-736x2013000200001, Alternate LINK

Title: Paratuberculose Em Ruminantes No Brasil

Subject: General Veterinary

Journal: Pesquisa Veterinária Brasileira

Publisher: FapUNIFESP (SciELO)

Authors: Elise M. Yamasaki, Marilene F. Brito, Rinaldo A. Mota, Douglas Mcintosh, Carlos H. Tokarnia

Published: 2013-02-01

Everything You Need To Know

What exactly is Johne's disease, and what types of animals are most affected?

Johne's disease, also known as paratuberculosis, is a chronic, progressive disease impacting livestock industries worldwide. It is caused by the bacterium Mycobacterium avium subspecies paratuberculosis (MAP). This disease primarily affects ruminants, including cattle, sheep, goats, and buffalo. The bacterium thrives within the intestinal cells of these animals, making them susceptible to the disease's devastating consequences.

What are the major economic consequences of Johne's disease for livestock producers?

The economic impact of Johne's disease is substantial, especially for dairy farms. Infections lead to decreased milk production, slower weight gain, and reproductive problems. Infected animals often have to be culled prematurely, or have lower slaughter value. These factors result in reduced productivity and increased veterinary costs, contributing to significant financial losses for livestock producers. In the United States, annual losses are estimated to reach 250 million USD.

How does Mycobacterium avium subspecies paratuberculosis (MAP) spread and persist in the environment?

Mycobacterium avium subspecies paratuberculosis (MAP) is a resilient bacterium that is central to Johne's disease. It persists in the environment and evades the host's immune system. The bacterium can survive outside of the host and is often spread through the commercialization of infected animals, contributing to interspecific transmission and agent dispersion, especially within Brazil. This persistence makes it a formidable challenge for livestock producers to control the spread of the disease.

Are there any potential links between Johne's disease and human health, and what's the current understanding?

There is a debate regarding the potential link between Mycobacterium avium subspecies paratuberculosis (MAP) and Crohn's disease, a long-term digestive issue in humans. Studies have detected MAP in raw and pasteurized milk, as well as in the blood of Crohn's patients. This connection highlights the importance of further research to determine MAP's potential role in human health and the implications for public health.

What measures are needed to control and prevent Johne's disease, especially in regions like Brazil?

To control and prevent Johne's disease, especially in places like Brazil, effective sanitary policies and control measures for Mycobacterium avium subspecies paratuberculosis (MAP) are essential. This includes the implementation of better sanitary controls to improve animal product quality on international markets. The focus should be on the development of better diagnostic tests. Moreover, molecular studies should be used to evaluate and refine these tests. This will aid in the detection of different strains to effectively control the disease and protect livestock.