1993 Four Corners hantavirus outbreak
Infection remains rare—about 10–50 cases of HPS occur each year in the US, most in spring and early summer and mainly in southwestern states.
The Four Corners region is the name given to the area where the borders of the US states of Arizona (AZ), Colorado (CO), New Mexico (NM), and Utah (UT) all meet each other.
[2] The area is part of the Colorado Plateau and is characterized by arid, rolling plains with sedimentary rocky features such as mesas, buttes, and canyons.
[6] Prior to the 1993 Four Corners outbreak, Old World hantaviruses were known to cause hemorrhagic fever with renal syndrome (HFRS) and a milder form of it called nephropathia epidemica (NE), which had mainly been observed in Asia and Europe.
An ambulance crew performed CPR as he was taken to the Gallup Indian Medical Center, where he was diagnosed with fluid buildup in the lungs (pulmonary edema), but even with emergency treatment he died.
The man had previously visited an outpatient clinic a few days prior due to fever, headache, cough,[9] and muscle pain, which were treated.
The death of the young man, a competitive marathon runner, due to sudden respiratory failure confused medical staff.
The woman's death, tentatively listed as acute respiratory distress syndrome (ARDS), was investigated in postmortem examination by University of New Mexico pathologist Patricia McFeeley.
McFeeley called the state health department in Santa Fe to report a possible outbreak of an unknown and deadly respiratory illness.
Tempest recalled having spoken to two physicians who had cared for young, previously healthy tribal members who died suddenly from an unknown respiratory illness.
Several suspicious cases from prior months were uncovered, including one from November the previous year, and on May 17 they notified the New Mexico Department of Health of their concerns.
[8][10][11] After learning of the situation, the press reported on May 27th[10] that an unexplained illness was killing tribe members in the Four Corners region, causing panic in the public.
After testing at a local laboratory continually yielded no positive results, samples were flown to the CDC in Atlanta, Georgia for immediate analysis.
By Friday, June 4, scientists of the Special Pathogens Branch of the CDC had tested IgM antibodies from nine patients with a panel of 25 different virus samples.
Nonetheless, an unknown hantavirus that specifically targeted pulmonary capillary endothelial cells was suspected by some members of the investigative team.
On June 10, reverse transcription polymerase chain reaction (RT-PCR) was used to obtain an RNA sequence from one segment of the virus's genome.
[8] By late June, testing had shown that about 30% of trapped eastern deer mice[10] and a small number of other rodents were carrying the hantavirus.
Physical examination of these people showed fever, rapid and shallow breathing (tachypnea), an abnormally fast heart rate (tachycardia), and low blood pressure (hypotension).
[17] A toll-free telephone hotline was created by the government to provide updated information about unexplained respiratory illness and to receive calls about suspected hantavirus cases throughout the country.
[20] National media flooded the local community with reporters, taking pictures of funerals, printing deceased people's names, and trying to interview victims' families with no respect for the traditional four-day mourning period in Navajo culture.
[14] Peterson Zah, the president of the Navajo Nation at the time, was a vocal critic of the sensationalist news coverage of the outbreak and the stigmatization of his community.
He said, "The story of Hanta Virus is a perfect example of an intercultural setting and the friction that lies just beneath the surface, and which explodes when unknowing outsiders trample on age-old customs.
Working with environmental scientists, it was demonstrated that the conditions of the 1991–1992 El Niño caused a relatively warm winter and rainy spring.
[10] The Navajo viewed mice in the home as a source of bad luck and disease, and their oral tradition spoke of past outbreaks in 1918, 1933, and 1934,[22] which they attributed to "disharmony", which leads to excess.
[23] Serum samples collected in 1991 and 1992 as part of the Navajo Health and Nutrition Survey were tested and showed that three out of 270 had antibodies to hantavirus, indicative of past infection.
[11] Just like in 1993, high precipitation following a severe El Niño in 1998 led to an increase in hantavirus cases in affected areas.
Based on environmental models of El Niño oscillations, it is possible to predict when future spikes in hantavirus cases will occur.
Sin Nombre virus is primarily associated with one species of deer mouse, and other hantaviruses discovered in North America follow the same pattern, each with their own natural reservoir.
[8] In the US, most HPS cases occur in rural areas[12] in southwestern[13] states and almost all infections are contracted by inhalation of aerosols containing rodent excretions at home or in the workplace.
[12] Human-to-human transmission of the Sin Nombre virus has never been recorded,[8] not even among health care workers exposed to infected people and tissues.
