Timeline of Pandemic H1N1 Warning

Introduction

 

At Veratect, we operate two operations centers based in the United States (one in the Washington, DC area and one in Seattle, WA) that provide animal and human infectious disease event detection and tracking globally.  Both operations centers use a distinct methodology inspired by the natural disaster and meteorology communities.  Our analysts handle information in the native vernacular language and have been thoroughly trained in their discipline, which include cultural-specific interpretation of the information.  We are currently partnered with 14 organizations that provide us with direct ground observations in 238 countries.  We are a multi-source, near-real time event detection and tracking organization with years of experience in this discipline.

 

April 6

 

Veratect reported local health officials declared a health alert due to a respiratory disease outbreak in La Gloria, Perote Municipality, Veracruz State, Mexico.  Sources characterized the event as a "strange" outbreak of acute respiratory infection, which led to bronchial pneumonia in some pediatric cases. According to a local resident, symptoms included fever, severe cough, and large amounts of phlegm. Health officials recorded 400 cases that sought medical treatment in the last week in La Gloria, which has a population of 3,000; officials indicated that 60% of the town’s population (approximately 1,800 cases) has been affected. No precise timeframe was provided, but sources reported that a local official had been seeking health assistance for the town since February.

 

Residents claimed that three pediatric cases, all under two years of age, died from the outbreak. However, health officials stated that there was no direct link between the pediatric deaths and the outbreak; they stated the three fatal cases were "isolated" and "not related" to each other.

 

Residents believed the outbreak had been caused by contamination from pig breeding farms located in the area. They believed that the farms, operated by Granjas Carroll, polluted the atmosphere and local water bodies, which in turn led to the disease outbreak. According to residents, the company denied responsibility for the outbreak and attributed the cases to "flu." However, a municipal health official stated that preliminary investigations indicated that the disease vector was a type of fly that reproduces in pig waste and that the outbreak was linked to the pig farms. It was unclear whether health officials had identified a suspected pathogen responsible for this outbreak.

 

The way we used this information was to simply flag an event as worthy of closer scrutiny and higher awareness, as there was absolutely no proof of true involvement of this company in the outbreak- a proper epidemiological investigation is required to prove such links.

 

Local health officials had implemented several control measures in response to the outbreak. A health cordon was established around La Gloria. Officials launched a spraying and cleaning operation that targeted the fly suspected to be the disease vector. State health officials also implemented a vaccination campaign against influenza, although sources noted physicians ruled out influenza as the cause of the outbreak. Finally, officials announced an epidemiological investigation that focused on any cases exhibiting symptoms since 10 March [1-6].

 

This information was available in our web portal to all clients, including CDC, WHO/PAHO and multiple US state and local public health authorities.

 

We do know, after checking our web site logs, that the Pan American Health Organization, the WHO Regional Office of the Americas, accessed this specific report in our system on April 10th and again on April 11th.

 

 

April 16

 

Veratect reported the Oaxaca Health Department (SSO) indicated that an unspecified number of atypical pneumonia cases were detected at the Hospital Civil Aurelio Valdivieso in Reforma, Oaxaca State, Mexico.  No information was provided about symptoms or treatment for the cases.  NSS Oaxaca reported that rumors were circulating that human coronavirus was spreading at the hospital; sources did not provide any response to these statements from the hospital or health officials.  

 

Laboratory samples were sent to Mexico City for analysis; results were expected to be released sometime next week.  According to NSS Oaxaca, health officials had intensified preventive measures aimed at mitigating further spread of the disease.  Sources reported that the SSO also implemented a sanitary cordon around the hospital [7-8].    

 

This information was pushed to CDC in an email alert notification provided by Veratect on April 16 and again on April 17:

 

"16 Apr 2009 4:14 PM GMT     Respiratory Disease     Detailed     Mexico (Reforma, Oaxaca)  Reforma: Atypical Pneumonia Cases Reported at Hospital", sent at "April 16, 2009 10:08:06 AM PDT" and again at "April 17, 2009 10:08:06 AM PDT" to CDC and at "April 16, 2009 10:27:13 AM PDT" to the California State Department of Health.

 

 

April 20

 

Veratect was urgently asked to provide access to the VeraSight Global platform on 20 April by a client in the US public health community, and indicated they had received word from their counterparts in Canada that Mexican authorities had requested support.  This client speculated whether notification of all southern U.S. border state public health authorities should be done and were confused as to why the CDC had not issued an advisory.  Veratect contacted the CDC Emergency Operations Center to sensitize them about the situation in Mexico. CDC indicated they were already dealing with the crisis of recently detected H1N1 swine influenza in California and possibly Texas.

 

April 21

 

Veratect reported the Oaxaca Health Department (SSO) confirmed two adults died from atypical pneumonia at the Hospital Civil Aurelio Valdivieso in Oaxaca, Oaxaca State, Mexico.  One of the cases was a 39-year-old female; the other case was an adult male of unspecified age.  After the deaths, the hospital established a quarantine in the emergency room due to initial concerns that avian influenza was responsible for the cases.  However, the SSO subsequently stated that neither avian influenza nor coronaviruses, including that which causes severe acute respiratory syndrome (SARS), were the source of infection.  Additionally, the SSO denied the cases represented an epidemic.  According to local sources, the SSO indicated that the atypical pneumonia cases were caused by an unspecified bacterial pathogen and were treatable with antibiotics.  Sources indicated a total of 16 additional patients exhibited signs of respiratory infection; none of these patients exhibited complications.          

 

Veratect sources indicated the 39-year-old female was treated at the hospital for five days before dying on 13 April.  This case was reportedly immunocompromised; in addition to acute respiratory symptoms, she also had diabetes and diarrhea.  The SSO contacted 300 people that had been in contact with the woman; sources stated that between 33-61 contacts exhibited symptoms of respiratory disease, but none showed severe complications.  The SSO characterized the incident as an "isolated case;" they noted that over 5,000 cases of pneumonia occur annually in Oaxaca.

 

Another local source reported the SSO launched surveillance measures in the former residential areas of the two fatal cases and in other targeted geographic areas.  No additional information was provided regarding the second fatal case at the hospital.  

 

Veratect reported that the Oaxaca State Congress Permanent Committee on Health had undertaken an investigation into the cases.  The committee inspected the Hospital Civil Aurelio Valdivieso on 20 April.  The director of the medical school at the University Autonoma "Benito Juarez" de Oaxaca (UABJO), along with other medical academics, publicly requested that national health authorities investigate the cases of atypical pneumonia.  No information was provided indicating that national health authorities plan to investigate the matter.  The director of the medical school also requested the SSO furnish evidence showing that the cases were negative for avian influenza, SARS, and other severe pathogens; his request was echoed by readers commenting on an online user forum.         

 

Veratect also reported the National Ministry of Health issued a health alert due to a significant increase in influenza cases during the spring season in Mexico.  Officials indicated that there have been 14 influenza outbreaks throughout the country.  The most heavily affected states are Baja California, Chihuahua, Distrito Federal (Mexico City), Hidalgo, Tlaxcala, and Veracruz.  Local case counts were not provided.

 

Officials stated that 4,167 probable cases of influenza, 313 of which were confirmed, have been reported throughout the country in 2009.  Case counts for suspected and confirmed influenza cases have tripled in 2009 as compared to the equivalent time period in 2008.  The National Institute of Respiratory Diseases recorded two fatal cases of influenza in 2009, but specific dates and locations were not provided.  

 

Health officials stated they were unsure precisely why the incidence of influenza had increased.  However, they believed the increased presence of influenza B, in combination with influenza A, was a contributing factor.  In response, officials advised anyone exhibiting influenza symptoms to avoid self-medication and seek medical care immediately.  Officials had also enhanced epidemiological surveillance for influenza.  Lastly, health officials had focused efforts on providing antiviral medications and influenza vaccinations to the most vulnerable segments of the population.  According to the Mexican Ministry of Health, 44.3% of the national population was vaccinated against influenza in 2005-2006.

 

Veratect sensitized the International Federation of Red Cross who in turn requested broader access be provided to the Pan-American Disaster Response Unit (PADRU).  Veratect moved to notify several US state and local public health authorities, providing the caveat the situation in Mexico remained unclear due to pending laboratory results.  Veratect reached out to World Health Organization (WHO) operations, informing them the Veratect team was on an alert posture and available for situational awareness support.  They indicated they and their subordinate, the Pan American Health Organization (PAHO) were now aware of the situation but had no further information.  Veratect also extended contact to the British Columbia Center for Disease Control and offered assistance in tracking the events in Mexico.  All contacts indicated laboratory results were pending [9-15].

 

 

April 22

 

Veratect reported the Oaxaca Health Department (SSO) indicated 16 employees at the Hospital Civil Aurelio Valdivieso in Oaxaca, Oaxaca State, Mexico had contracted respiratory disease.  However, the SSO denied these cases were connected to the recently identified cases of atypical pneumonia at the hospital.  No information was provided indicating how many employees work at the hospital or whether the number of respiratory disease cases was higher than average.  The source reported that "fear" persisted among hospital physicians concerning the possible presence of a deadly bacteria or virus circulating in the hospital.  One anonymous hospital employee criticized hospital management as "unfair" for not providing clear information regarding the first fatal atypical pneumonia case.

 

An additional source reported the cause of the atypical pneumonia cases remained unknown; it stated that bacteria or virus could have caused the cases.  In contrast, according to an 18 April report, the SSO indicated that the atypical pneumonia cases were caused by an unspecified bacterial pathogen and were treatable with antibiotics.  The reason for this discrepancy was unclear at this time.

 

The Instituto Mexicano del Seguro Social (IMSS), a national health entity, had now joined the SSO in responding to the cases; reports did not indicate the Mexican National Ministry of Health had joined in the response efforts.  The IMSS extended the sanitary cordon surrounding the hospital.  Patients exhibiting flu-like symptoms would be sent to the hospital’s epidemiology department for further study.  IMSS instructed physicians to hospitalize respiratory disease patients immediately if they meet certain standards for severity of symptoms.  Lastly, the hospital’s emergency room would remain closed for an additional 15 days so that cleaning and preventive disinfection could be carried out.

 

Veratect also reported the Mexican Ministry of Health indicated that an "unusual" outbreak of laboratory-confirmed influenza caused five deaths from 17-19 April 2009 in Mexico City, Mexico.  The deaths occurred at the following three hospitals: el Hospital de la Secretaria de Salud (2), el Institute Nacional de Enfermedades Respiratorias (2), and el Hospital Angeles del Pedregal (1).  According to unofficial sources, the fatal case count was higher than that provided by officials.  There were currently 120 influenza cases hospitalized throughout Mexico City.  National health officials indicated that influenza vaccines were sold out in Mexico City and that they were attempting to acquire additional supplies of the vaccine.  

 

At this point, the Mexican Health Secretary reportedly stated there was no influenza epidemic in Mexico City or throughout the rest of the county.  In response to the cases, the official stated health authorities would launch a public awareness and vaccination campaigns.  He stated that 400,000 vaccines would be administered, primarily to medical staff; it was unclear whether these efforts would be focused on Mexico City or any other geographic area.  Health officials also ordered the provision of special masks, gloves, and gowns for medical personnel that were in contact with influenza cases. 

 

A total of 13 fatal cases of influenza were reported in Mexico City in the past three weeks.  However, several other media sources reported that the 13 deaths were recorded since 18 March 2009; the reason for this discrepancy was unclear.  Sources reported a total of 20 fatal cases of influenza throughout Mexico over the disputed timeframe.  The other cases were located in San Luis Potosí (4), Baja California (2), and Oaxaca (1).  The Director of Epidemiology at the National Center for Epidemiological Surveillance and Disease Control characterized the outbreak as "quite unusual."

 

No information was provided indicating that the strain of influenza itself was unusual.  Rather, several sources indicated that it was "unusual" to record this many fatal influenza cases during this time of year.  Influenza cases normally peak from October to February, while these cases had occurred during Mexico’s spring season.

 

Canada announced a national alert for travelers returning from Mexico with respiratory disease, beginning a campaign of public media announcements. Potentially ill contacts were identified returning from Mexico and isolated in Canada.  Internet blogs begin to spin up.  CDC indicates concern about the events unfolding in Mexico.  Veratect sensitizes the US community physician social network managed by Ozmosis [16-28].

 

 

April 23

 

Veratect reported the Secretary General of the Oaxaca Ministry of Health Workers Union confirmed that a doctor and a nurse from the Hospital Civil Aurelio Valdivieso in Oaxaca, Oaxaca State, Mexico were under observation for suspected "atypical" pneumonia.  This contradicted statements made by the Oaxaca Health Department (SSO) on 22 April that 16 hospital employees contracted respiratory disease, but none of the cases exhibited atypical pneumonia.

 

The union official stated that a review by the Oaxaca State Board of Medical Arbitration indicated that the hospital faced serious difficulties caused by overcrowding; he stated that overcrowded conditions created a "breeding ground" for the spread of various epidemics.  According to the official, the hospital has 120 beds but the number of patients hospitalized had at times surpassed 240.      

 

Other sources reported that the Department of Livestock, Fisheries, Rural Development, and Feed (SAGARPA) declared on 20 April that Oaxaca, Mexico was free of avian influenza.  SAGARPA stated that authorities should remain vigilant in monitoring for the disease among birds. 

 

Canadian local health officials stated that a Rouge Valley resident with influenza-like illness was being monitored at Scarborough Centenary Hospital in Scarborough, Ontario.  The precaution was being taken in accordance with an alert issued by the Ministry of Health asking hospitals to watch for severe respiratory illnesses in travelers returning from Mexico.  Despite the warning, the Ministry had indicated that evidence is not suggestive of a novel pathogen or influenza strain, according to the source.  A representative for the Rouge Valley Health System stated that this case is being monitored related to the alert.  The source did not specifically indicate symptoms or that the person had traveled to Mexico.  No additional information regarding the case, including age or health status, was reported.  

 

The source stated that hospital employees were asking any patients admitted to the hospital if they had recently traveled to Mexico, which according to the source was a popular tourist destination for Durham-region residents.

 

Additional Canadian sources indicated Southlake Regional Health Centre officials treated a patient with influenza-like illness (ILI) who recently returned from Mexico.  The Ministry of Health recently notified Southlake, in addition to health units across the country, that an outbreak of severe respiratory disease was affecting areas of Mexico; ill travelers returning from that region with ILI symptoms were encouraged to be monitored.  Sources did not provide any specific information about the case, including age or current treatment status.  Information regarding the individual’s travel to Mexico was also not provided, including destinations and duration of time in country.

 

The Public Health Agency of Canada (PHAC) noted that an Ontario resident who returned from Mexico on 22 March experienced severe respiratory illness, but has fully recovered and was not considered connected to the current situation.  Veratect recently reported on 30 March that a public official from Cornwall, Ontario was hospitalized with an unknown illness following a trip to Mexico; however, it is unclear if the cases are related, or if this was the case referenced by PHAC officials [29-39].

 

On 23 April, Veratect assessed the situation and noted the following:

 

Affected areas:

 

Oaxaca, Distrito Federal, San Luis Potosi, Baja California

 

Distance to nearest international airport:

 

·      Oaxaca airport, located approximately 150 miles from Reforma, is connected via non-stop air traffic to Houston

·      Mexico City (Distrito Federal) airport is connected via non-stop air traffic to many cities in the US, Canada, Europe and Latin America, with the most outbound traffic to Los Angeles, Frankfurt, Houston, Dallas, and Amsterdam

·      San Luis Potosi airport is connected via non-stop air traffic to Dallas and Houston

·      Mexicali airport in Baja California is connected via non-stop traffic to Los Angeles

·      Veracruz airport is connected via non-stop air traffic to Houston

 

Large mass gatherings:

 

Semana Santa (~April 3 - 12, Palm Sunday to Easter Sunday), which is Mexico’s second largest holiday.  Mexico’s population is approximately 90% Catholic, which results in substantial population migration patterns during this time period.  For instance, in Ixtapalapa (in Mexico City), one million people visit for Semana Santa.  Other well-known sites for the holiday include Patzcuaro, San Cristobal de las Casas (Chiapas), and Taxco.  Veratect notes substantial population migration has just occurred that could facilitate the spread of respiratory disease.

 

Civil Unrest:

 

The recent surge in organized crime and drug-related violence in Mexico, including homicides, kidnappings, extortion, and theft, has disproportionately impacted Mexican states along the Pacific Coast and U.S.-Mexico border.  This factor may confound situational awareness of respiratory disease in Mexico and contribute to problems in epidemiological investigation and response measures.  Baja California is one of five states within this region that currently accounts for more than 75 percent of Mexico's drug-related homicides, and has recorded high levels of drug seizures and police corruption cases. Veracruz, a state with high drug cartel activity in the Gulf of Mexico, has recorded little violence, while the state of Oaxaca to the southwest, recently recorded the assassination of a political party leader. Mexico City, in the center of the country, recently arrested a major drug cartel leader, and recorded few homicides this month. The levels of unrest in Hidalgo, San Luis Potosi, and Tlaxcala, however, are very low, and have not reported a single homicide related to organized crime in the past month.

 

Veratect issues notification to additional public health authorities in two states.  Veratect reaches out to the Pan American Health Organization emergency operations team but is unable to establish contact.  Veratect notes no publicly available English language reporting from ProMED, HealthMap, FluNET, CDC, ECDC, or WHO about the unfolding events in Mexico.  Many of Veratect’s clients, including Canadian, ask why an alert has not been issued by the US to sensitize their healthcare community.

 

April 24

 

Veratect continues to process a dramatic increase in reporting on the situation in Mexico.

 

WHO requests access to the Veratect system.  Veratect is aware of laboratory samples from Mexico are positive for swine flu H1N1, a novel virus.  World media are now aware of the situation in Mexico.  CDC issues a press statement, as does WHO.

 

Veratect notifies the United Kingdom National Health Service NaTHNaC (National Travel Health Network and Centre).  The NaTHNaC website as of April 24^th contained no public announcement of the situation in Mexico.  Response from their senior analyst did not indicate awareness.  Veratect notifies the private US clinical laboratory community and activates a Twitter feed (twitter.com/veratect) to enable more rapid updating of information until WHO and CDC were able to come up to date with their public reporting.

 

 

References

 

1.    Reportan deceso de tres menores; lurgarenos reponsabilizan a empresa; Alerta epidemiologica en Perote por brote de males respiratorios [Death of three children reported; villagers blame company. Perote epidemiological alert for outbreaks of respiratory disease]. La Jornada. 4/5/09. Accessed 4/6/09 at http://www.jornada.unam.mx/2009/04/05/index.php?section=estados&article=025n1est

2.    Realizan barrido sanitario por foco de infección en Perote, Veracruz [Health cordon enacted in Perote due to focus of infection]. SDP Noticias. 4/5/09. Accessed 4/6/09 at http://sdpnoticias.com/sdp/contenido/2009/04/05/369612     

3.    Alerta epidemiológica en La Gloria, Perote por brote de males respiratorios. Acusan a Granjas Carroll [Epidemiological alert in La Gloria, Perote due to respiratory disease outbreak. Carroll Farms Accused]. Zapateando.  4/5/09. Accessed 4/6/09 at http://zapateando.wordpress.com/2009/04/05/alerta-epidemiologica-en-la-gloria-perote-por-brote-de-males-respiratorios-acusan-a-granjas-carroll/

4.    Proliferación de moscas, posible causa del brote epidemiológico en Perote [Proliferation of flies considered possible cause of epidemiological outbreak in Perote]. Proceso. 4/3/09.  Accessed 4/6/09 at http://www.proceso.com.mx/noticias_articulo.php?articulo=67717     

 

5.    Aumentan 15% enfermedaded en zonas serranas: SSA [15% increase in disease in highland areas]. Imagen del Golfo. 4/2/09. Accessed 4/6/09 at  http://www.imagendelgolfo.com.mx/resumen.php?id=99804

6.    Rechazan epidemia bronco respiratoria en Perote [Officials deny bronco-respiratory epidemic in Perote]. El Dictamen Online. 4/2/09. Accessed 4/6/09 at [http://www.eldictamen.org/ver_nota.php?noticia=5193&seccion=Estado&year=2009

7.    Atienden cases de neumonia atipica [Attending cases of atypical pneumonia]. Adiario Oaxaca. 4/16/09. Accessed 4/16/09 at http://www.adiario-oaxaca.com.mx/2009/04/16/atienden-casos-de-neumonia-atipica/

8.     Presunto brote de neumonía atípica en Hospital Civil de Oaxaca [Suspected outbreak of atypical pneumonia in Oaxaca Civil Hospital]. NSS Oaxaca. 4/15/06. Accessed 4/16/09 at http://www.nssoaxaca.com/index.php/ciudad/10-oaxaca/12513-presunto-brote-de-neumonia-atipica-en-hospital-civil-de-oaxaca

9.    Los diputados, ‘responsablemente’, actuarán hasta el lunes [Officials, responsibly, to act on Monday]. Diario Despertar de Oaxaca. 4/17/09. Accessed 4/21/09 at http://www.diariodespertar.com.mx/Agenda/8713-Los-diputados-responsablemente-actuarn-hasta-lunes.html.

10. Piden especialistas intervención federal ante posible emergencia sanitaria [Demanding intervention from federal specialists against possible health emergency]. Diario Despertar de Oaxaca. 4/18/09. Accessed 4/21/09 at http://www.diariodespertar.com.mx/Agenda/8773-Piden-especialistas-intervencin-federal-ante-posible-emergencia-sanitaria.html

11. Emergencia Sanitaria [Health Emergency]. Diario Despertar de Oaxaca. 4/16/09. Accessed 4/21/09 at http://www.diariodespertar.com.mx/Agenda/8662-Emergencia-Sanitaria.html.

12. Descartan SSO brote epidémico en el Hospital Civil [SSO Dismissed Outbreak in Civil Hospital]. InfoMinuto. 4/16/09. Accessed 4/21/09 at http://www.infominuto.com/index.php/component/content/article/2799?joscclean=1&comment_id=812

13. Descartan SSO brote epidémico en el Hospital Civil [SSO Dismissed Outbreak in Civil Hospital]. Quadratin. 4/16/09. Accessed 4/21/09 at http://www.quadratinoaxaca.com.mx/noticias/nota,26322/.

14. SSO Discarded outbreak in the civil hospital. Pandemic Information News. 4/20/09. Accessed on 4/21/09 at http://pandemicinformationnews.blogspot.com/2009/04/sso-discarded-outbreak-in-civil.html

15. Descartan SSO brote epidémico en el Hospital Civil [SSO Dismissed Outbreak in Civil Hospital]. El Imparcial. 4/17/09. Accessed 4/21/09 at http://www.imparcialenlinea.com/getPrint.php?id=80564

16. Amplían el cerco sanitario al IMSS [IMSS extends health cordon]. 4/21/09. Diario Despertar de Oaxaca. Accessed 4/22/09 at http://www.diariodespertar.com.mx/Agenda/8923-Amplan-cerco-sanitario-IMSS.html

17. Tensa calma y zozobra privan en el Hospital Civil [Tense calm and anxiety deprive the civil hospital]. 4/20/09. Diario Despertar de Oaxaca. Accessed 4/22/09 at http://www.diariodespertar.com.mx/Agenda/8879-Tensa-calma-zozobra-privan-Hospital-Civil.html     

18. Title unknown. ADN Sureste. Date Unknown. Accessed on 4/22/09 at http://www.adnsureste.info/index.php?news=11747

19. Causa alerta en DF inusual brote de influenza [Alert in DF caused by unusual outbreak of influenza] 4/22/09. Terra. Accessed 4/22/09 at http://www.terra.com.mx/articulo.aspx?articuloId=817210&ref=1     

20. Brote de influenza provoca muerte de 5 personas [Influenza outbreak causes the death of 5 people] 4/22/09. Tiempos de la Internet. Accessed 4/22/09 at http://www.timesoftheinternet.com/espanol/35776.html     

21. Reportan 20 muertes por influenza en el país, una en Oaxaca [20 deaths from influenza reported in the country, one in Oaxaca] 4/22/09. NSS Oaxaca. Accessed 4/22/09 at http://www.nssoaxaca.com/index.php/nacional/6-nacional-politica/12877-reportan-20-muertes-por-influenza-en-el-pais-una-en-oaxaca     

22. Influenza causa 20 muertes en México revelan autoridades [Authorities reveal 20 deaths from influenza in Mexico] 4/22/09. Accessed 4/22/09 at http://www.milenio.com/node/203310     

23. Encienden focos rojos por brotes de influenza en el DF [Red flags raised due to influenza outbreaks in DF] 4/22/09. Organizacion Editorial Mexicano. Accessed 4/22/09 at http://www.oem.com.mx/elsoldemexico/notas/n1133933.htm     

24. Alerta casos de influenza en el pais [Alert for cases of influenza in the country]. 4/22/09. El Agora. Accessed on 4/22/09 at http://www.elagoradechihuahua.com/Alerta-Salud-por-casos-de,13659.html     

25. Alerta Salud por casos de influenza en el país  [Health alert for cases of influenza in the country] 4/22/09. Excelsior Online. Accessed 4/22/09 at http://www.exonline.com.mx/diario/noticia/primera/pulsonacional/alerta_salud_por_casos_de_influenza_en_el_pais/577357     

26. Desatan alerta casos atípicos de influenza [Warning issued due to cases of atypical influenza] 4/22/09. Excelsior Online. Accessed 4/22/09 at http://www.exonline.com.mx/diario/noticia/primera/pulsonacional/desatan_alerta_casos_atipicos_de_influenza/576990     

27. Canada on alert after respiratory illnesses reported in Mexico. 4/22/09. Calgary Herald. Accessed 4/22/09 at http://www.calgaryherald.com/Health/Canada+alert+after+respiratory+illnesses+reported+Mexico/1523180/story.html     

28. Descartan José Ángel Córdova epidemia de influenza  [José Ángel Córdova discarded influenza epidemic] 4/22/09. Milenio.com. Accessed on 4/22/09 at http://www.milenio.com/node/203315     

29. Médico y enfermera, contagiados, confirman [Doctor and nurse, contracted confirm] 4/22/09. Diario Despertar de Oaxaca. Accessed 4/23/09 at http://www.diariodespertar.com.mx/Agenda/8974-Mdico-enfermera-contagiados-confirman.html     

30. Descartan casos de 'influenza aviar' en Oaxaca  [Exclude cases of 'bird flu' in Oaxaca ] 4/20/09. Al Minuto. Accessed 42309 at http://www.infominuto.com/index.php/al-minuto/34-al-minuto/2831-descartan-casos-de-influenza-aviar-en-oaxaca     

31. Oaxaca libre de influenza aviar: Sagarpa  [Oaxaca free of avian influenza: Sagarpa] 4/20/09. NSS Oaxaca. Accessed 4/23/09 at http://www.nssoaxaca.com/index.php/ciudad/10-oaxaca/12731-oaxaca-libre-de-influenza-aviar-sagarpa     

32. Local hospitals watching for Mexican flu-type illness. 4/23/09. Durhamregion.com. Accessed on 4/23/09 at http://www.newsdurhamregion.com/news/life/article/124690     

33. Alert Issued After Serious Mystery Ailment Affects Canadians Returning From Mexico. 4/23/09. City News. Accessed on 4/23/09 at http://www.citynews.ca/news/news_33963.aspx     

34. Canadians told to be on alert for Mexico illness. 4/23/09. CTV Toronto. Accessed on 4/23/-09 at http://toronto.ctv.ca/servlet/an/local/CTVNews/20090423/mexico_illness_090423/20090423/?hub=TorontoNewHome     

35. Travel by Canadians to foreign countries, top 15 countries visited. 4/23/09. Statistics Canada. Accessed 4/23/09 at http://www40.statcan.gc.ca/l01/cst01/arts37a-eng.htm

36. Hospital issues flu warning to travelers . 4/23/09. Yorkregion.com. Accessed on 4/23/09 at http://www.yorkregion.com/article/90990     

37. News in Georgiana, Title unknown. 4/23/09. Yorkregion.com. Accessed on 4/23/09 at http://www.georginaadvocate.com/News/Regional%20News/article/90988     

38. Travel advisory warns of severe respiratory illness in Mexico. 4/23/09. CBC News. Accessed on 4/23/09 at http://www.cbc.ca/health/story/2009/04/23/respiratory-illness-flu-mexico.html     

39. Canada on alert after respiratory illnesses reported in Mexico. 4/22/09. Calgary Herald. Accessed 4/23/09 at http://www.calgaryherald.com/Health/Canada+alert+after+respiratory+illnesses+reported+Mexico/1523180/story.html