NEJM: Outbreak investigation reveals potential for human-to-human transmission of the Andean virus

December 7, 2020 /--- In a new study, an international scientific team found that the "super-spreader" event and extensive human contact contributed to the outbreak of Hantavirus pulmonary syndrome (HPS) in a small village in Argentina in 2018-2019.
the results were published in the December 3, 2020 issue of the New England Journal of Medicine under the title "'Super-Spreaders' and People-to-People Transmission of Andes Virus in Argentina."
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paper, the authors report on the genetic, clinical and epidemiological characteristics of outbreaks caused by andes viruses, members of the Hantan virus family.
their analysis may help clinicians and public health officials control outbreaks of other viral diseases with similar transmission patterns, including COVID-19.
virus is carried by wild rodents native to South America and can be infected by contact with infected animals or their faeces.
like other Hantan viruses, Andean virus infection can cause serious and often fatal respiratory diseases in humans, known as Hantan virus lung syndrome (HPS).
, the Andean virus is the only known human-to-human transmission of the Hantan virus.
who are in direct contact with an infected person or his or her body fluids, or who are in close contact with the patient, may also be infected.
currently, there is no approved vaccine or drug to treat the disease.
the study, high viral loads in large-scale social activities and infected individuals contributed to human-to-human transmission of the Andean virus during outbreaks.
the authors worked with local health authorities to create a near-complete epidemiological "picture" to reconstruct the specific transmission of 34 confirmed cases.
traced the source of the outbreak to a single spill and recorded an overall 32 percent case mortality rate.
human-to-human transmission of the Andean virus was first described in 1996, the latest outbreak is the most extensive human-to-human transmission recorded to date.
genome analysis of the authors showed striking similarities between the Andean virus sequences that led to the 2018-2019 outbreak and the 1996 outbreak.
understanding which genomes "signatures" meet the necessary mechanisms for human-to-human transmission may help scientists develop new therapies to treat Andean virus infections.
the authors found that droplets or aerosol virus particles may have been the route of infection during the widespread human-to-human transmission of the 2018-2019 outbreak.
also noted that symptoms can occur within 9 to 40 days of infection.
, however, they point out that there may be a narrow contagious window.
usually occurs on the first day of fever in infected patients.
interesting is that there is no clear correlation between the individual who transmits the virus and the severity of his or her disease.
"This important observation suggests that all HPS cases should be equally managed for the likelihood of transmission of the virus, regardless of the severity of the disease," said Dr. Gustavo Palacios, co-author of the paper and director of molecular biology at the U.S. Army Institute of Infectious Disease Medicine.
addition, we need to reassess the threat posed by this virus.
lack of existing medical responses, strong transmission potential and high case mortality rates should all be of concern.
" findings have the potential to help clinicians and public health officials respond to future outbreaks.
, as with current preventive measures against COVID-19, social distance and the use of appropriate personal protective equipment can effectively control transmission.
addition, widespread contact tracing and self-segregation have led to a significant decline in transmission.
, co-lead author of the paper, said, "Although less than 10 percent of cases occur in hospital settings, the threat to clinicians and hospital staff should not be underestimated."
doctors should remember that during the 1996 outbreak, when proper personal protective equipment was not used, many health care workers became ill and some died.
study also looked at cytokines in patients to determine the type of immune response present in PATIENT patients caused by the Andean virus, the authors said.
cytokines are proteins that assist in intercellular communication in the immune response.
concluded that although no clear mechanism has been found, it is more common to have a broad, dysfunctional immune response in patients.
, co-author of the paper, said, "We hope that by further exploring this apparent immune disorder, we will expand our understanding of how different Hantan virus species cause Hantan virus lung syndrome."
better understanding of how our immune system responds to Andean virus infection will certainly help clinicians better treat serious cases and pave the way for the development of new treatment interventions.
based on these comprehensive data, the authors confirm the need to study the emergence, super-transmission, human-to-human transmission and pathological patterns of the Andean virus in order to improve public health response strategies.
, co-author of the study, said, "A range of techniques and expertise to determine human-to-human transmission and super-transmission events may be available for outbreaks other than the Andean virus outbreak."
we hope this approach can serve as a model for future investigations into human-to-human transmission and identification of super-transmission events.
, according to Palacios, the study was based on research by the Genomics Science Center of the U.S. Army Institute of Infectious Disease Medicine during outbreaks of Ebola virus disease in West Africa and the Democratic Republic of the Congo, as well as the introduction of the Zika virus to the United States.
, "While we are proud of this study and our track record, we believe this is just the beginning," said Paulacios.
have an integrated approach to tracking spills is a long-term goal that we strive for every day.
(Bioon.com) : 1. Valeria P. Martínez et al. "Super-Spreaders" and Person-to-Person Transmission of Andes Virus in Argentina. New England Journal of Medicine, 2020, doi:10.1056/NEJMoa2009040.2.Outbreak investigation reveals 'super-spreader' potential of Andes virus。