Valley Fever After House-Building Trips to Baja California, 2018

On August 8, 2018, the New York City Department of Health and Mental Hygiene told CDC about two high school students hospitalized with pneumonia of unknown cause. Both had just come back from community service trips building houses near Tijuana, in Baja California, Mexico. They developed fever 9 and 11 days after the trip, then a rash and chest symptoms, and repeated antibiotics did not help. Both were eventually diagnosed with coccidioidomycosis — a fungal disease known as valley fever.

Valley fever cases among U.S. residents returning from community service trips to Baja California, July–August 2018. CDC / MMWR

The outbreak

Because two healthy young people had fallen so ill, health officials looked for more cases through the school group, a trip-coordinating organization and Epi-X alerts. By October 15, 2018:

• eight clinically diagnosed cases in four states — Kansas, Maryland, Michigan and New York — among people on several service trips in June–July 2018
• all male: five high school students and three adults
• four hospitalized — one in intensive care, one needing a chest tube for fluid around the lung, one in hospital more than 10 days

The patients were on seven separate trips run by churches, high schools and community groups, coordinated by two organizations, with about 225 travelers from six states (also Missouri and Washington). Seven of the eight had dug or built at the same house south of Tijuana — the likely source for most. Health departments warned every traveler of the risk, and authorities in Mexico were alerted; no cases linked to the outbreak were found there.

About valley fever

• It is caught by breathing in dust or soil carrying the fungus's spores.
• About 40% of infected people get flu-like symptoms 1–3 weeks after exposure; about 5%–10% develop serious lung problems, and about 1% a disseminated (spreading) form.
• It is endemic in the southwestern United States, northern Mexico, and parts of Central and South America, and has been rising in California, which borders Baja California.
• In Mexico it is not a mandatory reportable disease and standard blood tests are often unavailable, so little is known about it there. Tijuana was thought to have less of it than other parts of Mexico — but outbreaks have struck travelers doing construction before, on service trips to Tecate and Hermosillo.

Lessons

• Doctors: ask about travel, and think of valley fever in anyone with chest symptoms — with or without a rash — back from northern Mexico or endemic parts of the United States.
• Trip organizers planning digging or construction in these areas should warn participants, and consider:
• • wetting the soil
  • hiring professionals trained in excavation safety
  • keeping upwind of digging when possible
  • wearing at least an N-95 respirator approved by CDC's National Institute for Occupational Safety and Health or cleared by the Food and Drug Administration during dusty work
• Better early diagnosis, treatment and surveillance could mean fewer misdiagnoses and better outcomes.

Sources

Based on Toda M, Gonzalez FJ, Fonseca-Ford M, et al., "Notes from the Field: Multistate Coccidioidomycosis Outbreak in U.S. Residents Returning from Community Service Trips to Baja California, Mexico — July–August 2018," MMWR Morbidity and Mortality Weekly Report, volume 68, Centers for Disease Control and Prevention; a work of the United States government in the public domain.