The confirmation of First case of screwworm in a Doberman dog within Mexico City This has raised alarms among Mexican health authorities and drawn the attention of animal health specialists in Europe as well, where this plague is closely monitored due to its enormous impact on livestock and pets. Although, for now, it is an isolated incident, the case serves as a reminder of how quickly an infestation of this type can spread if action is not taken promptly.
The affected animal is a 12-year-old Doberman living in the rural area of TopilejoIn the Tlalpan borough, a dog was treated at a veterinary clinic after a wound infested with larvae was detected at the base of its left ear. Following this discovery, the National Service for Agrifood Health, Safety and Quality (Senasica) and the Ministry of Agriculture and Rural Development activated a special protocol to prevent the incident from escalating into a wider outbreak—an approach considered crucial in Europe when an initial outbreak of this pest occurs.
How the first case was detected in the Doberman dog in Tlalpan
The case was officially reported on April 26When the Topilejo veterinary clinic reported to Senasica the presence of suspected myiasis in a dog, the attending veterinarian identified larvae consistent with the disease. Cattle screwworm (Cochliomyia hominivorax) in a wound located at the base of the dog's left ear.
According to information gathered by the authorities, the injury originated in a dog fightThis left the tissue exposed, allowing the fly to lay its eggs. From there, the larvae began feeding on the living tissue, causing the myiasis seen in the video later shared on social media, where maggots can be seen moving in the animal's wound.
The elderly Doberman, He was immediately admitted for veterinary treatment and is currently under clinical supervision and epidemiological monitoring. As part of the biosecurity protocols, the house where the animal resides has been disinfected to eliminate any remaining sources of infestation.
The authorities have emphasized that, as of today, No secondary cases have been identified in other animals in the area. The combination of altitude and climatic conditions in Topilejo leads specialists to believe that this is an "incursion," that is, an isolated case which, with the decisive measures already underway, should be contained without leading to sustained transmission.
What is the screwworm and why is it a concern for veterinarians and farmers?
The protagonist of this health alert is the cattle screwwormThe larval stage of the fly Cochliomyia hominivorax. Unlike other flies that feed on decaying matter, this species lays its eggs in wounds from live animalsUpon hatching, the larvae penetrate healthy tissue and consume it from the inside out, making this myiasis a medical and economic problem of the first magnitude.
In a matter of hours or a few days, the larvae can generate severe infections, tissue necrosis, intense pain, and feverIf left untreated, the animal can suffer severe muscle and organ damage, systemic complications, and even death. It doesn't only affect dogs and cats: cattle are among the most vulnerable, but it can also occur in other mammals and even humans.
In Spain and other European countries, agricultural and livestock authorities maintain a extremely strict control Regarding this pest, an uncontrolled outbreak would be a very serious blow to the primary sector. The case of Mexico City, although geographically distant, is being closely followed in European animal health circles as an example of how to act upon the first detection of an outbreak.
Nationally in Mexico, the situation is delicate: official data indicates that More than 600 infected animals in 25 stateswith a significant focus on states such as Veracruz, Oaxaca, Puebla, Chiapas, and San Luis Potosí. Since the start of the plague in late 2024, [number of] cases have been recorded. tens of thousands of caseswith a particular impact on livestock farming areas. This expansion is what makes the appearance of the first case within the capital especially significant.
Symptoms of screwworm myiasis in dogs, cats, and cattle
The key to avoiding serious complications is detect the warning signs as soon as possibleVeterinarians insist that any open wound on an animal, especially in hot and humid climates, should be monitored very carefully to rule out the presence of larvae.
Among the symptoms that may suggest a screwworm infestation in Dogs and cats are:
- Open wounds that they do not heal or they worsen rapidly.
- Injuries with strong bad smellpresence of pus or bloody secretion.
- Direct observation of worms or larvae moving on the surface or inside the wound.
- Inflammation, marked pain when touching the area, and defensive behavior in the animal.
- Decline, apathy, loss of appetite and fever.
- Constant restlessness, obsessive licking or scratching of the affected area.
In cattle and other production species, in addition to these signs, the following can be observed: decrease in performanceWeight loss and reduced milk or meat production are common symptoms. The larvae can burrow deep into the skin and tissues very quickly, so a seemingly small wound can conceal a much more extensive myiasis.
In extreme cases, when the infestation is massive or affects sensitive areas, the animal can become critically ill within days. Therefore, European veterinary practice emphasizes consulting a professional. for any wound that smells bad, oozes pus, or shows rapid changesThis is something that Mexican specialists are also now emphasizing to the population.
Can the screwworm affect people?
Although most documented cases involve domestic animals and livestockScrewworm myiasis can also occur in humans. It's not very common, but flies can take advantage of the situation. open wounds, skin ulcers, or very moist areas of the skin to lay their eggs.
When this happens, people may notice Intense pain, swelling, and a feeling of movement under the skinThe lesion usually produces foul-smelling discharge, and upon close examination, larvae may be visible. In these circumstances, the recommendation is clear: seek urgent medical attention to have the larvae removed, the wound cleaned, and receive appropriate treatment.
In environments like Spain or the rest of Europe, where there is a strict medical and veterinary controlHuman cases of this type of myiasis are rare, but authorities remind the public that international travel and the movement of people and animals necessitate continued vigilance. Recent experience in Mexico reinforces this message of caution.
Containment and surveillance measures following the Topilejo case
Following the confirmation of the first case in the Doberman in Tlalpan, the Mexican government, through Senasica and the Ministry of Agriculture, launched a containment strategy in the affected areaThe objective is twofold: to protect the animal population of Mexico City and to prevent any expansion into nearby productive areas.
Among the measures implemented, the following stand out:
- Reinforcement of the passive and active epidemiological surveillance in the Topilejo area and neighboring municipalities.
- Realization of retrospective and prospective research to track possible previous or new outbreaks.
- Complete disinfection of the home where the affected dog resides and its immediate surroundings.
- Formation of house-to-house search teams, with epidemiological surveys of animal owners.
- Information campaigns in the field, on social media and in the press to promote rapid reporting of suspected cases.
The authorities maintain a permanent surveillance in the rural area of Tlalpan They have activated immediate response protocols with specialized personnel, laboratories, and inter-institutional coordination. This same philosophy of “detecting quickly and acting even faster” is applied in Europe when there is a risk of the entry of exotic pests that affect animal health.
Although for the moment it is insisted that it is a isolated incursionThe national context, with thousands of cases accumulated since 2024, demands that we not let our guard down. Each new potential outbreak can pose a risk to the livestock sector and animal welfare, which is why citizen collaboration has become a key element of the operation.
Recommendations for pet owners and livestock farmers (also applicable in Europe)
Experts point out that much of the prevention against the screwworm is based on very simple hygiene and monitoring routineswhich can be applied both in Mexico and in Spain or any European country with a climate conducive to flies at certain times of the year.
In the case of Dogs and cats, it is advisable to:
- Check the skin, ears, tail and areas with folds or little hair daily.
- Clean and disinfect any wound immediately., however small it may seem.
- Avoid leaving wounds exposed in environments with many flies.
- Maintain good hygiene in yards, gardens and areas where animals sleep.
- Do not allow pets to come into contact with carrion, dead animals, or accumulated garbage.
- Consult a veterinarian if your wounds smell bad, ooze, or do not improve.
- Keep up to date deworming and regular veterinary check-ups.
For livestock farmers and farm managers In Mexico and Europe, guidelines include frequent livestock inspection, proper management of organic waste, prompt disposal of dead animals, and the use of preventative treatments when indicated by official veterinary services. These practices are common in European Union countries, where experience controlling other myiasis and vector-borne diseases has shown that prevention costs far less than a large-scale outbreak.
In a context of climate change, with higher temperatures and prolonged warm seasonsEuropean experts believe that pests such as the screwworm should be included in integrated surveillance plans, especially in areas with high livestock density or abundant susceptible wildlife.
What happened in Mexico City with the first case of screwworm in a Doberman dog This illustrates how a single, poorly treated wound can become the entry point for a plague with serious health and economic consequences. The swift response of the authorities, the deployment of tracking teams, and the emphasis on prevention are essentially the same tools recommended in Spain and the rest of Europe to keep these types of threats at bay: thoroughly inspecting animals, treating any wounds without ignoring them, and promptly reporting anything amiss.
