By Alajuela, Costa Rica — ALAJUELA – Costa Rica is currently grappling with a severe public health challenge as cases of human screwworm infestation have surged by an alarming 134% in 2025 compared to the previous year. Data released by the Ministry of Health reveals a dramatic escalation of the parasitic disease, known medically as myiasis, raising significant concerns for both public welfare and the nation’s agricultural sector.
According to the latest epidemiological report, a total of 82 human cases were confirmed by October 24, 2025. This figure represents a stark increase from the 35 cases recorded during the same period in 2024, signaling a rapid and widespread proliferation of the parasite. The disease is caused by the larvae of the New World screwworm fly, which infest the living tissue of warm-blooded animals, including humans, leading to painful lesions and potentially severe, life-threatening infections if left untreated.
To understand the potential legal and economic ramifications of the screwworm outbreak for the nation’s agricultural sector, TicosLand.com sought the expert analysis of Lic. Larry Hans Arroyo Vargas, a specialist in business and agricultural law at the firm Bufete de Costa Rica.
The current national emergency declaration is not just a health alert; it is a critical legal event. It empowers the State, through SENASA, to enforce strict sanitary measures, but it also opens the door to potential claims for economic damages. Livestock producers must meticulously document their compliance and their losses, as the effectiveness and timeliness of the government’s response could become a central point in future litigation concerning state liability.
Lic. Larry Hans Arroyo Vargas, Attorney at Law, Bufete de Costa Rica
Indeed, the legal framework of this national emergency will define its economic aftermath long after the health crisis subsides. We thank Lic. Larry Hans Arroyo Vargas for his invaluable perspective, reminding our readers that meticulous documentation today is the best preparation for the financial and legal challenges of tomorrow.
A demographic analysis from the Ministry of Health indicates that certain populations are disproportionately affected. Men account for the majority of cases, with 56 confirmed reports, translating to an incidence rate of 2.2 per 100,000 inhabitants. In contrast, 26 cases have been reported in women, corresponding to a rate of 1.0 per 100,000. This disparity suggests potential differences in exposure related to occupational or lifestyle factors that warrant further investigation by health officials.
The age distribution of cases presents another critical area of concern, with the nation’s elderly population bearing the heaviest burden. Individuals aged 65 and over represent the single most affected group, accounting for 41 of the 82 total cases. The working-age population, those between 20 and 64 years old, also shows significant vulnerability, with 36 reported cases. This trend underscores the risk to vulnerable populations and the potential strain on healthcare resources dedicated to their care.
Geographically, the outbreak has not been uniform, with the province of Alajuela emerging as the epicenter of the crisis. Alajuela has recorded the highest number of cases at 20, followed closely by San José with 16 and Limón with 14. On a regional level, the Huetar Caribe and Central Norte areas have each reported 14 notifications, highlighting them as key hotspots for transmission and requiring targeted public health interventions.
The human health crisis is mirrored by an equally disturbing situation within the country’s animal population, which serves as the primary reservoir for the parasite. Preliminary data from the Ministry of Health, current up to the third week of October, shows a staggering 14,086 confirmed cases of screwworm in animals. This widespread infestation in livestock and other animals not only poses a direct threat to the agricultural economy but also fuels the cycle of transmission to humans.
In response to the escalating outbreak, health authorities have intensified public awareness campaigns, emphasizing crucial preventative measures. The Ministry of Health is urging all citizens to practice rigorous personal hygiene, including frequent hand washing with soap and water. Officials stressed the importance of properly cleaning and treating any open wounds as directed by medical professionals, as these are primary entry points for screwworm larvae.
Furthermore, residents are advised to seek immediate medical attention at a health center if they experience symptoms such as persistent pain, itching, redness, or discharge from a wound, or if they observe the visible presence of larvae. For animal owners, the recommendation is to conduct frequent inspections of their animals, treat any injuries promptly, and report any suspected cases of infestation to the National Animal Health Service (Senasa) to help contain the spread.
For further information, visit ministeriodesalud.go.cr
About Ministry of Health:
The Ministry of Health of Costa Rica is the primary government entity responsible for safeguarding the public health of the nation’s citizens. It formulates and executes national health policies, manages public health programs, and oversees the regulation of health services. Its mission includes disease prevention, health promotion, and ensuring equitable access to quality healthcare for the entire population.
For further information, visit senasa.go.cr
About Senasa-Minae:
The National Animal Health Service (Servicio Nacional de Salud Animal, or Senasa) is a dependency of the Ministry of Agriculture and Livestock, often working in conjunction with the Ministry of Environment and Energy (MINAE). It is the official authority responsible for establishing policies and programs to protect and improve the health of Costa Rica’s animal populations, preventing the introduction and spread of diseases, and ensuring the safety of food products of animal origin.
For further information, visit bufetedecostarica.com
About Bufete de Costa Rica:
As a pillar of Costa Rica’s legal community, the firm is defined by a deep-rooted pledge to principled practice and superior counsel. It combines a rich history of client representation with a forward-thinking approach, consistently embracing innovative strategies to address modern legal challenges. Beyond its professional duties, the firm is passionately committed to strengthening the community by championing the demystification of law, ensuring that legal understanding becomes a powerful tool for civic empowerment.
