Situation at a glance
On 11 May 2023, the United States of America Centers for Disease Control and Prevention (US CDC) notified the Mexico General Directorate of Epidemiology (DGE) of five cases with central nervous system infection (CNSI) in the United States of America. All five cases were females with a history of undergoing surgical procedures performed under spinal anaesthesia in Mexico. The surgeries were performed in two private clinics, located in the city of Matamoros, Tamaulipas state, on the border with the USA.
Laboratory test results from samples collected from patients in the USA and Mexico were consistent with meningitis caused by pathogenic fungi.
Fungal meningitis is rare but can be fatal and requires immediate medical care.
WHO continues to monitor the epidemiological situation based on the latest available information.
Description of the situation
On 11 May 2023, the US CDC notified the Mexico’s DGE through the International Health Regulations National Focal Point (IHR NFP), the identification of five female cases with CNSI in the USA, with a history of undergoing surgical procedures performed under spinal anaesthesia in two private clinics in a city in Mexico, bordering the USA.
As of 26 May 2023, the health authorities from Mexico and the USA have reported a total of 20 cases presenting with signs and symptoms compatible with CNSI, including two deaths reported by the US CDC. Patients presented to the hospital with symptoms including headache, fever, nausea, vomiting, sensitivity to light, and fainting after receiving surgical procedures in two private clinics located in the city of Matamoros, Tamaulipas state in Mexico, on the border with the USA between January and April 2023.
The Mexico Epidemiological Diagnosis and Reference Institute (InDRE per its acronym in Spanish) has received five samples of cerebrospinal fluid (CSF) that tested positive for a fungus, Fusarium solani by real-time polymerase chain reaction (RT-PCR). Additionally, according to the health authorities from the USA, the laboratory results from nine suspected cases were consistent with meningitis, of which two CSF and two blood samples showed elevated levels of (1,3)-beta-D-glucan, a biomarker for fungal infection. Two pan-fungal PCR tests were negative.
According to the investigation performed, a total of 547 people had these procedures between January and April 2023 in the concerned two private clinics, of whom 304 (56%) reside in Mexico, 237 (43%) in the United States, and one in Canada.
Epidemiology of the disease
Several species of bacteria, viruses, fungi, and parasites can cause meningitis, an inflammation of the tissues surrounding the brain and spinal cord. Fungal meningitis can develop after a fungal infection spread from somewhere else in the body to the central nervous system. It can be fatal and requires immediate medical care. While rare, medical and surgical procedures can lead to fungal meningitis if medical devices or medications are contaminated with fungi, or if proper infection prevention control practices are not taken. This type of healthcare-associated infection can lead to severe illness or death. Healthcare-associated fungal meningitis outbreaks have occurred among patients who received spinal anesthesia.
Public health response
The United States of America and Mexico Health Authorities are investigating additional cases that may be associated with this outbreak in both countries. The response measures include:
In the United States of America:
- On 8 May 2023, through the Emerging Infections Network , US CDC learned of two unusual meningitis cases in Texas with prior spinal anesthesia.
- On 16 May, the US CDC published a level 2 travel health notice related to fungal infections following procedures performed under spinal anaesthesia in Mexico with recommendations for the public and clinicians. Additionally, on 24 May, an interim recommendation for diagnosing and managing cases of suspected fungal meningitis associated with spinal anesthesia administered in Matamoros, Mexico, were also published by the US CDC.
- On 17 May, the US CDC published a Health Alert Network related to an outbreak of suspected fungal meningitis in patients who underwent procedures performed under spinal anesthesia in Matamoros, Mexico.
- State and local health departments have initiated contacting and follow-up of people through telephone calls and home visits who are known to have had procedures performed under spinal anesthesia at these two clinics since January 2023. Instructions are given to people to go to their nearest health clinic, urgent care, or emergency room for diagnostic testing including a magnetic resonance imaging and a lumbar puncture.
In Mexico:
- Epidemiological investigations are ongoing in Matamoros, Mexico. In addition, the DGE is working with State Health Services and the Matamoros Health Jurisdiction on operational definitions.
- Mexico health authorities are strengthening active epidemiological surveillance for meningitis in Tamaulipas state to achieve timely identification.
- On 13 May, Tamaulipas Health Authority closed the two private healthcare facilities where these surgical procedures were performed.
- A follow-up of exposed people was initiated through telephone calls and home visits.
- On 19 May, the Mexico IHR NFP notified PAHO/WHO of an outbreak of CNSI associated with spinal anaesthesia in Matamoros, Tamaulipas state.
WHO risk assessment
Fungal meningitis cases following a medical/surgical procedure are very infrequent and unusual. In 2012, the US CDC investigated a multistate outbreak of fungal meningitis and other infections among patients who received contaminated preservative-free methylprednisolone acetate ( MPA) steroid injections; 753 cases were reported, including 64 deaths in 20 States in the USA.
The source, vehicle, and the transmission route for the current outbreak remains unknown, although the investigations are ongoing. A fungal infection is suspected based on preliminary information provided by the health authorities from Mexico and the USA.
Each year, more than a million people from the USA participate in medical tourism. In 2017, more than 1.4 million Americans sought health care in a variety of countries around the world. These medical tourists commonly travel to Mexico, Canada, and countries in Central America, South America, and the Caribbean. At present, there is no evidence to suggest any secondary spread from these cases of health care associated fungal meningitis The involved healthcare facilities where the procedures were undertaken have been closed since 13 May. However, there is an ongoing investigation and follow up of people who may have been exposed to fungal infections. This may lead to additional cases being reported until the follow up of people exposed to such procedure is completed.
WHO continues to monitor the epidemiological situation and review the risk assessment based on the latest available information.
WHO advice
As the outbreak’s source is yet to be established, WHO Member States must stay vigilant. It is critically important for affected Member States to identify any possible cases, establish the causal chain, and determine if any substandard/falsified products or procedures could be related. Investigation of these cases will assist in rapid containment at the disease source to prevent additional suspected cases.
WHO recommends the continuation of laboratory analyses, case identification and clinical care, follow-up of potentially exposed people, outbreak investigation to identify the agent, the source, the vehicle, and the transmission route, implementation of measures to prevent further infections, and enhancement of Infection Prevention and Control (IPC) measures.
IPC measures in health facilities should be reinforced to prevent healthcare-associated transmission. Attention should be paid to ensure injection safety practices are adhered to, including standards being met for medical device disposal or reprocessing (if reusable). Processes used for the storage, transport, and preparation of sharps, syringes, and vials should be examined to ensure sterility prior to use in local healthcare facilities. Use of multidose vials should be avoided. IPC practices should be reviewed and reinforced in operating theaters to ensure they are adhered to, including appropriate personal protective equipment use, before aseptic procedures, including skin antisepsis for safe administration of spinal anesthesia, as well as ensuring environmental cleaning.
WHO does not recommend any specific different measures for travellers visiting Mexico. In case of symptoms suggestive of meningitis during or after travel, travelers are encouraged to seek medical attention and share their travel history with their healthcare provider.
WHO advises against the application of any travel or trade restrictions on Mexico and the United States of America based on the current information available on this event.
Further information
- World Health Organization (WHO). Meningitis. 17 April 2023. Available from: https://www.who.int/news-room/fact-sheets/detail/meningitis
- Centers for Disease Control and Prevention (US CDC) Interim Guidance for Diagnosis and Management of Cases of Suspected Fungal Meningitis Associated with Epidural Anesthesia Administered in Matamoros, Mexico. Available from: Interim Guidance Matamoros FM Outbreak 5_20_23 – Fungus Education Hub(link is external)
- Centers for Disease Control and Prevention (US CDC.). Fungal Meningitis. 25 May from 2021.United States of America. Available from: https://www.cdc.gov/meningitis/fungal.html(link is external)
- Fungal Infections Associated with Contaminated Steroid Injections. 25 March 2016. Available from: https://doi.org/10.1128/microbiolspec.EI10-0005-2015(link is external)
- Centers for Disease Control and Prevention (US CDC). Special MSGERC Webinar – May 26, 2023. Available from: Special MSGERC Webinar – May 26, 2023 – YouTube(link is external)
- Centers for Disease Control and Prevention (CDC-U.S.). Travel Notice: Fungal Infections Following Surgical Procedures in Mexico. Available from: https://wwwnc.cdc.gov/travel/notices/alert/fungal-infections-mexico(link is external)
- Centers for Disease Control and Prevention (CDC-U.S.). Health Alert Network: Outbreak of Suspected Fungal Meningitis in U.S. Patients who underwent Surgical Procedures under Epidural Anesthesia in Matamoros, Mexico. Available from: https://emergency.cdc.gov/han/2023/han00491.asp
- Centers for Disease Control and Prevention (CDC-U.S.). Multistate Outbreak of Fungal Meningitis an Other Infections. Available from: https://www.cdc.gov/hai/outbreaks/meningitis.html(link is external)
- Centers for Disease Control and Prevention (CDC-U.S.). Medical Tourism: Travel to another country for medical care. Available from: https://wwwnc.cdc.gov/travel/page/medical-tourism(link is external)
- James E. Dalen. Medical Tourist: Incoming and Outgoing. The American Journal of Medicine, Vol 132, No.1. January 2019. Available from: https://www.amjmed.com/article/S0002-9343(18)30620-X/fulltext#tbl0001(link is external)
- Pan American Health Organization / World Health Organization. Meningitis of unknown origin. December 10, 2022, Washington, D.C.: PAHO/WHO; 2022 https://www.paho.org/en/file/120929/download?token=2PchTURu(link is external)
- Fungal Infections Associated with Contaminated Steroid Injections. 25 March 2016. Available from: https://doi.org/10.1128/microbiolspec.EI10-0005-2015
Citable reference: World Health Organization (1 June 2023). Disease Outbreak News; Outbreak of suspected fungal meningitis associated with surgical procedures performed under spinal anaesthesia – the United States of America and Mexico. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2023-DON470