ETIDIOH - NEW

  Abstract Mexico has experienced recurrent viral epidemics of substantial intensity, including hyperendemic dengue, COVID-19, and recent reports of avian influenza A (H5N1) infections in birds , which pose an ongoing risk of zoonotic transmission . Mexico was also the location for the earliest detection of the pdmH1N1 virus during the 2009 influenza A pandemic. Under a One Health framework , markets represent a unique opportunity for low-cost virus monitoring at the human-animal interface . Under the hypothesis that these represent sentinel sites for an early virus detection , we implemented a pilot surveillance program at the central market of Merida city, Yucatan , Mexico, considered a regional hotspot for multiple and recent viral outbreaks . Longitudinal sampling was carried out over 11 months at 1-to-6-week intervals from April 2022 to February 2023 . We used multi-type surveillance in mosquitoes, live poultry, and wastewater . All samples were screened using RT-qPCR . Positi...

  Abstract Background   Infection of backyard and poultry with low pathogenicity avian influenza LPAI A(H5N2) viruses has occurred in Mexico since 1994, and the first human infection caused by this influenza virus was detected in 2024 . Since its emergence in the Americas , frequent reassortments between high pathogenicity avian influenza HPAI A(H5N1) and LPAI viruses has occurred. In September 2025 , the Instituto Nacional de Enfermedades Respiratorias of Mexico City identified an unsubtypeable influenza A virus infection in a young adult patient later determined to be a reassortant HPAI (H5N2) virus with a clade 2.3.4.4b HA .  Methods   We analyzed clinical and epidemiologic data from this patient. Respiratory samples were tested for influenza RT-qPCR assays . Genomic sequence and phylogenetics analyses were performed to provisionally assign a new genotype to the novel HPAI A(H5N2) reassortant virus.  Results   The patient presented with fever and tachypn...

  • New human cases {1,2}:  -- From 30 September to 5 November 2025 , based on reporting date, the detection of influenza A(H5N1) in one human , A( H5N2 ) in one human and A( H9N2 ) in two humans were reported officially.   • Circulation of influenza viruses with zoonotic potential in animals :  -- High pathogenicity avian influenza (HPAI) events in poultry and non-poultry animal species continue to be reported to the World Organisation for Animal Health (WOAH).{3}  -- The Food and Agriculture Organization of the United Nations (FAO) also provides a global update on avian influenza viruses with pandemic potential.{4}  • Risk assessment {5}:  -- Sustained human to human transmission has not been reported in the above human infection events.  -- Based on information available at the time of this risk assessment update , the overall public health risk from currently known influenza A viruses detected at the human-animal interface has not changed...

{Excerpt} This Week : [Date of report - Country - Province / Region District / City - Sex - Age - Condition at time of reporting  - Subtype of virus] 1) .../10/2025 - Cambodia - Takeo Province - F - 14 - Hospitalised - H5N1  2) 16/10/2025 - Cambodia - Kampong Speu Province - F - 3 - Under intensive care - H5N1 (...) [Place of occurrence - No. of cases  (No. of deaths) - Details] -- Bangladesh - 1(0)  - Avian influenza A(H5) :  1) Sylhet Division : A boy with onset on July 27, 2025.  -- Chinese Mainland - 4(0)  - Avian influenza A( H9N2 ):  - Guangdong Province :  1) An individual with onset in February 2025. The case was retrospectively reported.  - Guangxi Zhuang Autonomous Region :  2, 3) Two individuals with onset in February 2025. Both cases were retrospectively reported.   - Tianjin Municipality :  4) An individual with onset in February 2025. The case was retrospectively reported.  -- Mexico - 1(0)  - ...

  Abstract Avian influenza A viruses pose ongoing threats to human and animal health, with H7 subtypes causing outbreaks globally . In Mexico , highly pathogenic H7N3 viruses have circulated in poultry since 2012, causing sporadic human infections . Here we analyzed genetic markers in hemagglutinin sequences from Mexican H7N3 isolates and conducted serological assays on human populations with poultry exposure . Our results show conserved avian-like receptor binding sites , thus limiting human adaptation , alongside antigenic drift and acquisition of glycosylation sites likely driven by vaccination. Serological testing of 1103 individuals revealed no detectable antibodies against H7N3, indicating a naïve population . Phylogenetic analyses revealed multiple virus clades circulating regionally. These findings suggest that while current H7N3 viruses have limited capacity for sustained human transmission, the lack of population immunity underscores the importance of continued surveillan...

  Abstract Background :  In Mexico, two Mammarenavirus genotypes have been identified : Real de Catorce virus and Ocozocoautla de Espinosa virus (OCEV), which are found in rodents (Neotoma leucodon and Peromyscus mexicanus). Mammarenaviruses from clade B cause mild to severe infectious diseases in humans , particularly in South America. A 1967 outbreak in Chiapas, Mexico, was potentially linked to the OCEV. Materials and Methods :  Between 2017 and 2020, we collected bats across southern/southeastern Mexico to identify Mammarenavirus reservoirs. We analyzed 81 liver samples from 14 bat species using nested PCR. For quality control, we synthesized and OCEV S-region fragment into an ampicillin-resistant pUC57 plasmid, cloned in One Shot Stbl3 chemically competent E. coli. Results :  Here, we report the first detection of a Mammarenavirus (OCEV) in an Artibeus lituratus bat from Sabancuy, Campeche , southeastern Mexico. This finding represents the third Mammarenavirus r...

{Excerpt} Situation at a glance As of 18 April 2025, a total of 2318 measles cases , including three deaths , have been confirmed in six countries in the WHO Region of the Americas , an 11-fold increase compared to the same period in 2024 .  The majority of cases have occurred among people between 1 to 29 years , who are either unvaccinated or have an unknown vaccination status .  Additionally, most cases are imported or linked to importation.  Measles is a highly contagious, airborne viral disease that can lead to severe complications and death.  Although it is preventable with two doses of the vaccine, over 22 million children worldwide did not receive their first dose of the vaccine in 2023. This has contributed to a global rise in measles cases in 2024, which heightens the risk of imported infections, particularly from unvaccinated travellers arriving from areas where the virus is actively circulating.  WHO is working closely with countries in the WHO Region...

Abstract We performed serologic surveillance for selected arthropod-borne viruses (arboviruses) in bats and opossums in the Lacandona Rainforest, Chiapas, Mexico , in 2023–2024. Sera were collected from 94 bats of at least 15 species and 43 opossums of three species. The sera were assayed by the plaque reduction neutralization test (PRNT) for antibodies to eight orthoflaviviruses ( dengue viruses 1–4, St. Louis encephalitis virus , T’Ho virus, West Nile virus, and Zika virus ) and one alphavirus (chikungunya virus; CHIKV). Twelve (12.8%) bats and 15 (34.9%) opossums contained orthoflavivirus-specific antibodies . One bat (a Jamaican fruit bat) was seropositive for Zika virus , and 11 bats contained antibodies to an undetermined orthoflavivirus , as did the 15 opossums. All bats and most opossums seropositive for an undetermined orthoflavivirus had low PRNT titers, possibly because they had been infected with another (perhaps unrecognized) orthoflavivirus not included in the PRNTs. Anti...

  Situation at a glance On 2 April 2025, the International Health Regulations (IHR) National Focal Point (NFP) for Mexico notified the World Health Organization (WHO) of the country’s first laboratory-confirmed human infection with an avian influenza A(H5N1) virus in the state of Durango .  In response, local and national health authorities have implemented a range of measures to monitor, prevent, and control the situation.  There have been reports of A(H5N1) outbreaks in birds in Durango , although the exact source of infection in this case remains under investigation .  To date, no further cases of human infection with influenza A(H5N1) linked to this case have been identified.  In accordance with the IHR (2005), any human infection caused by a new influenza A virus subtype is considered a potentially significant public health event and is subject to mandatory notification to WHO.  Based on the information currently available on this and previous cases, W...

{Automatic translation. Edited.}  www.gob.mx/salud The Ministry of Health reports the death of the first human case of avian influenza A (H5N1) in Mexico .  It is reported that a three-year-old girl diagnosed with avian influenza A(H5N1) and a resident of Durango died today at 1:35 a.m. due to respiratory complications resulting from the infection.  It is a viral disease that affects birds (wild and domestic), mammals and occasionally humans.  Local, state, and federal health, environmental, and agricultural authorities continue prevention and control measures within the context of One Health. So far, 38 human contacts of the case have been sampled, all of which have tested negative .  No additional human cases have been identified, and the risk of further cases is considered low.  X:  @SSalud_mx   Source: Ministry of Health,  https://www.gob.mx/salud/prensa/secretaria-de-salud-informa-la-defuncion-del-primer-caso-humano-de-influenza-avi...

{Auto translated} www.gob.mx/salud The Ministry of Health reports the detection of the first human case of avian influenza A (H5N1) in Mexico .  The case occurred in a three-year-old girl residing in the state of Durango . On April 1 , the Institute of Epidemiological Diagnosis and Reference (InDRE) confirmed the result of influenza A ( H5N1 ). The patient initially received treatment with oseltamivir and is currently hospitalized in a tertiary care unit in the city of Torreón, where her condition is reported to be serious .  Once the case was confirmed , the following actions were immediately implemented:  -- Notification to the World Health Organization, in accordance with the protocol established for this purpose in the International Health Regulations.  Health -- Health personnel from the Durango and Coahuila Health Services were trained in relation to the National Guide for the preparation, prevention and response to a zoonotic influenza outbreak or event at the...

Abstract In April 2024, the Instituto Nacional de Enfermedades Respiratorias of Mexico City identified a case of unsubtypeable Influenza A in a 58-year-old immunocompromised patient with renal failure due to diabetic nephropathy and bacterial peritonitis. Through sequencing the M, NS, NA, NP, and HA complete segments, we identified an H5N2 influenza virus with identity of 99% with avian influenza A(H5N2) from Texcoco, Mexico, in 2024. This case is the first reported with direct evidence of human infection caused by the H5N2 influenza virus; the relationship of the virus with the severity of his condition remains unknown. Source: Viruses,  https://www.mdpi.com/1999-4915/17/2/205 _____