---
title: "Mexico reports 53% increase in flesh-eating screwworm cases since July"
description: "Aug 27 (Reuters) - Mexico has recorded 5,086 cases of flesh-eating screwworm in animals as of August 17, a 53% jump from the number of cases reported in July, according to Mexican government data seen by Reuters on Wednesday."
type: "NewsArticle"
publisher: "Daily Maverick"
site: "https://www.dailymaverick.co.za"
section: "Newsdeck"
author: "Reuters"
author_url: "https://www.dailymaverick.co.za/author/reuters/"
canonical_url: "https://www.dailymaverick.co.za/article/2025-08-28-mexico-reports-53-increase-in-flesh-eating-screwworm-cases-since-july/"
published: "2025-08-28T05:16:48"
updated: "2025-08-28T05:16:49"
lang: "en-ZA"
word_count: 305
---

# Mexico reports 53% increase in flesh-eating screwworm cases since July

> Aug 27 (Reuters) - Mexico has recorded 5,086 cases of flesh-eating screwworm in animals as of August 17, a 53% jump from the number of cases reported in July, according to Mexican government data seen by Reuters on Wednesday.

By Reuters · Published 28 August 2025, 07:16 SAST · Updated 28 August 2025, 07:16 SAST

## Key points
- As screwworms feast their way north from Mexico, ranchers are left sweating bullets over a 50% surge in cases that could turn Texas's cattle industry into a $1.8 billion buffet for these flesh-eating parasites.
- Active screwworm cases have surged to 649, raising alarms among conservationists and ranchers.
- The parasites, primarily affecting cattle, have also been found in dogs, horses, and sheep across Mexico.
- An outbreak that began in 2023 is inching closer to the U.S., threatening Texas's $1.8 billion cattle industry.
- The CDC confirmed the first U.S. human case linked to travel from an outbreak area in El Salvador.

## Content

By Heather Schlitz and Cassandra Garrison

The updated numbers, which have not been previously reported to the public, showed 649 currently active cases.

"That's absolutely concerning," said Neal Wilkins, CEO of conservation and cattle group East Foundation. "Having a 50% increase in month-over-month numbers, particularly in the extreme heat, means they haven't gotten it under control."

The vast majority of cases were identified in cattle, though Mexican government data also showed infestations in dogs, horses and sheep.

Screwworms are parasites that eat warm-blooded animals alive and can devastate cattle herds and local wildlife.

Since an outbreak began in 2023, screwworms have advanced northward from Central America into Mexico and inched closer to the U.S. American ranchers and livestock industry players have closely monitored the fly's progress northward, fearing an infestation that would cost Texas, the biggest U.S. cattle-producing state, about $1.8 billion, according to U.S. estimates.

Female screwworm flies lay hundreds of eggs in wounds on any warm-blooded animal. Once the eggs hatch, the larvae use their sharp, hooked mouths to burrow through living flesh — feeding, enlarging the wound and eventually killing their host if left untreated.

On Sunday, [Reuters reported](https://www.reutersconnect.com/all?search=all%3AL1N3UG068&linkedFromStory=true) the first human case in the United States of travel-associated New World screwworm from an outbreak-affected country. The case, investigated by the Maryland Department of Health and the U.S. Centers for Disease Control and Prevention, was confirmed by the CDC as New World screwworm on August 4, and involved a patient who returned from travel to El Salvador, HHS spokesman Andrew G. Nixon said in an email to Reuters.

The U.S. Department of Agriculture is sending a team to Mexico in two weeks to verify that Mexico is following protocol to prevent screwworm's northern spread, Deputy Secretary Stephen Vaden said on Tuesday.

(Reporting by Heather Schlitz and Cassandra Garrison; Editing by Leslie Adler)