Saturday, December 09, 2023

CDC HAN Advisory #00502: Severe and Fatal Confirmed Rocky Mountain Spotted Fever among People with Recent Travel to Tecate, Mexico


Credit CDC

#17,806

We often go weeks or even months between CDC HAN (Health Alert Network) advisories, but over the past 48 hours the CDC has released two, with the first on Clade I Mpox surveillance, and the second - released last night - on a cluster of fatal and severe Rocky Mountain Spotted Fever (RMSF) cases in Southern California/Baja California. 

All 5 patients (3 fatal) had recently visited or resided in the city of Tecate, state of Baja California, Mexico (roughly 35 miles south and east of San Diego on the Mexican American border). 

While called Rocky Mountain Spotted Fever, this tick borne bacterial disease can be carried, and transmitted by a variety of ticks across the country. That said, since 2010 the Southwestern United States and parts of Northern Mexico have seen increased activity. 

While Lyme disease is the best known tick borne threat by the public, the CDC lists a growing number of diseases carried by ticks in the United States, including: 

Anaplasmosis, Babesiosis , Ehrlichiosis, Heartland Virus, Powassan Disease, Rickettsia parkeri Rickettsiosis, Rocky Mountain Spotted Fever (RMSF), STARI (Southern Tick-Associated Rash Illness), Tickborne relapsing fever (TBRF), Tularemia, and 364D Rickettsiosis .

RMSF responds well to Doxycycline, but can rapidly progress if not administered early.  In order to raise awareness,and improve treatment times, the CDC has issued the following HAN Advisory. 

I'll have a bit more after the break.

Severe and Fatal Confirmed Rocky Mountain Spotted Fever among People with Recent Travel to Tecate, Mexico



Distributed via the CDC Health Alert Network
December 8, 2023, 4:15 PM ET
CDCHAN-00502

Summary

The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory to notify healthcare providers and the public about an outbreak of Rocky Mountain spotted fever (RMSF) among people in the United States with recent travel to or residence in the city of Tecate, state of Baja California, Mexico. RMSF is a severe, rapidly progressive, and often deadly disease transmitted by the bite of infected ticks, although many patients do not recall being bitten by a tick. Doxycycline is the treatment of choice for patients of all ages. As of December 8, 2023, five patients have been diagnosed with confirmed RMSF since late July 2023; all had travel to or residence in Tecate within 2 weeks of illness onset. RMSF is endemic in multiple border states in northern Mexico, including but not exclusive to Baja California, Sonora, Chihuahua, Coahuila, and Nuevo León. Healthcare providers should consider RMSF in their differential diagnosis of patients who have reported recent travel to Tecate, Mexico, or other areas of northern Mexico and subsequently develop signs or symptoms of an unexplained severe febrile illness. Consider initiating doxycycline based on presumptive clinical and epidemiologic findings, and do not delay treatment pending the result of a confirmatory laboratory test. Early treatment with doxycycline saves lives.

Background

RMSF is endemic across northern Mexico and areas of the southwestern United States. In these regions, the pathogen (Rickettsia rickettsii) can be transmitted by brown dog ticks (Rhipicephalus sanguineus) which are closely associated with domestic dogs in urban and peri-urban environments. From July to December 2023, CDC and the California Department of Public Health identified five patients with RMSF who developed the disease within 2 weeks following travel to the city of Tecate in the state of Baja California, Mexico. All patients presented to hospitals in southern California. Four patients were under the age of 18 years. Three patients were U.S. residents, and two were residents of Mexico. All five patients were hospitalized, and three died.

RMSF is a rapidly progressive disease and without early administration of doxycycline can be fatal within days. RMSF signs and symptoms can be relatively mild and non-specific during the first 1–4 days of illness and include a low-moderate fever, headache, gastrointestinal symptoms, abdominal pain, myalgia, rash, and edema around the eyes and on the back of hands. Patients with more advanced disease, generally on or after day 5 of illness, may develop altered mental status, coma, cerebral edema, respiratory compromise, necrosis, and multiorgan system damage. The disease is rapidly progressive, and half of all people who die from this disease succumb within 8 days of illness onset. Untreated disease is often fatal, and the case fatality rate of RMSF in Mexico can exceed 40%.

Recommendations for Healthcare Providers
Diagnosis
  • Know that RMSF signs and symptoms can include fever, headache, and rash.
    • A faint macular rash usually appears on the arms and lower extremities on or about 2–4 days after onset of symptoms and becomes petechial on or about day 5 or 6 of illness. Some patients never develop a rash.
    • The disease progresses rapidly if left untreated and is frequently deadly if not treated with doxycycline within the first 5 days of illness.
    • Children younger than 10 years old are five times more likely than adults to die from RMSF. Doxycycline is the treatment of choice for patients of all ages, including young children.
    • RMSF is a multisystem disease and can also involve the lungs, heart, kidneys, and central nervous system.
  • Consider RMSF when evaluating patients presenting with RMSF signs and symptoms, including fever, headache, and rash, especially those with a travel history to Tecate or other areas in northern Mexico endemic for RMSF in the past 2 weeks.
  • The absence of a classical “spotted” rash does not exclude the diagnosis, particularly during the first few days of illness.
  • Inquire about recent travel history and exposure to ticks or tick-infested dogs when evaluating patients with signs and symptoms suggestive of RMSF.
Diagnostic Testing

If RMSF is suspected, whole blood and serum samples obtained from acutely ill people should be evaluated for Rickettsia by molecular and serologic testing methods available at commercial laboratories, state public health laboratories, or CDC.
  • Do not delay or withhold treatment pending receipt of laboratory test results or based on an initial negative test result.
  • Polymerase chain reaction (PCR) amplification can be performed on whole blood, rash biopsy, or postmortem tissue but has low sensitivity early in the disease.
  • Serologic testing can also be performed on paired acute and convalescent serum samples collected 2–4 weeks apart. Serologic testing for detection of antibodies is frequently negative in the first week of illness.
  • Diagnostic testing at CDC may allow retrospective laboratory confirmation in patients who die from the infection.
  • If Rickettsia-specific testing is not available in a jurisdiction, specimen submission to CDC can be coordinated through your state or local health department.
Treatment
  • Doxycycline is the recommended antibiotic treatment for RMSF in adults and children of all ages, including pregnant people. Intravenous formulations are required for patients with severe nausea and vomiting and for patients who are obtunded.
  • If RMSF is suspected, initiate treatment with doxycycline immediately. Do not delay treatment pending laboratory confirmation. Early treatment saves lives.
  • In cases of severe doxycycline allergy, rapid desensitization procedures in an inpatient setting may be considered. Physicians should carefully weigh the benefits of doxycycline use and the risks of adverse effects on a case-by-case basis with an infectious disease or other specialist.
Reporting

RMSF is a nationally notifiable disease. Healthcare professionals and clinical laboratories should report all cases to their local, state, territorial, or tribal health department.

Recommendations for the Public
  • Seek medical attention if you or a family member has traveled to Tecate or another city in northern Mexico where RMSF has been known to occur, and develops fever, headache, or rash within 2 weeks of return to the United States.
  • Protect against tick bites by treating your dog for ticks, using EPA-registered insect repellent, and wearing protective clothing.
  • Perform thorough tick checks on yourself and children after outdoor activities or when around dogs with ticks. Promptly remove any ticks.
  • Learn about RMSF symptoms and seek medical help if you suspect that you or a family member may have this disease.
For More Information
RMSF

Having gone through my own Lyme disease nightmare (misdiagnosed for several years in the 1990s), I have a special appreciation for the risks from tick borne diseases.  A few others we've covered in this blog in the past year include:

Viruses: Epidemiology of Severe Fever with Thrombocytopenia Syndrome (SFTS) in Dogs and Cats in Taiwan

Pakistan: CCHF Dispatches From Balochis­tan

CDC MMWR: Geographic Distribution of Suspected Alpha-gal Syndrome Cases — United States, January 2017–December 2022

UKHSA: HAIRS Risk Assessment On TBE (Tick-borne encephalitis) in the UK

EID Journal: Fatal Case of Heartland Virus Disease Acquired in the Mid-Atlantic Region, United States

EID Journal: Nosocomial Severe Fever with Thrombocytopenia Syndrome in Companion Animals, Japan, 2022

For those who want more information, the CDC offers the following 52-page PDF booklet on Tickborne Diseases of the United States. 


 

Posted by at