Nine days ago, in Argentina’s Growing Hantavirus Outbreak, we looked at an unusually large cluster of hantavirus cases – which began in late November – in the small village of Epuyén in the Patagonian province of Chubut.
At that time there were reportedly 28 cases and 10 deaths, including media reports of a 29 year-old nurse who died in neighboring Santiago, Chile (see Hantavirus travels to Argentina and arrives in Chile: nurse dies in Santiago).
Today the World Health Organization has published a large update and risk assessment on the outbreak. Although the number of new cases have dropped markedly over the past 3 weeks (n=3), due to the long incubation period (1-8 weeks) of the Andes Hantavirus, additional cases could turn up.
I’ve only posted excerpts from a much longer WHO report. Follow the link to read it in its entirety.
Hantavirus Pulmonary Syndrome – Argentine Republic
Disease outbreak news
23 January 2019
On 19 December 2018, the Argentinian Ministry of Health and Social Development issued an epidemiological alert regarding an increase in cases of hantavirus pulmonary syndrome (HPS) in Epuyén, Chubut Province. Between 28 October 2018 – 20 January of 2019, a total of 29 laboratory-confirmed cases of HPS, including 11 deaths have been reported in Epuyén, Chubut Province. Epuyén has a population of approximately 2 000 persons, and Chubut Province is located in Patagonia in southern Argentina.
The index case had environmental exposure prior to symptom onset on 2 November, and subsequently attended a party on 3 November. Six cases who also attended the party experienced the onset of symptoms between 20-27 November 2018.
An additional 17 cases, all of whom were epidemiologically-linked to previously confirmed cases, experienced symptom onset between 7 December 2018 and 3 January 2019 (Figure 1). Potential human-to-human transmission is currently under investigation.
Of the confirmed cases, 59% were female, and had an incubation period ranging from 8 to 31 days. Approximately 50% of these confirmed cases reported symptoms within the past three weeks. Cases were confirmed by ELISA IgM u-captura or by polymerase chain reaction (PCR).
As of 17 January 2019, a total of 98 asymptomatic contacts have been identified and are being monitored for the potential development of symptoms.
In Argentina, four endemic regions have been identified: North (Salta, Jujuy), Centro (Buenos Aires, Santa Fe, and Entre Ríos), Northeast (Misiones) and Sur (Neuquén, Río Negro, and Chubut). Between 2013 and 2018, an average of 100 confirmed cases were registered annually, with the provinces of Buenos Aires, Salta, and Jujuy having the highest numbers of cases. Between 2013 and 2018, 114 confirmed deaths from hantavirus were reported in Argentina, with a case-fatality rate of 18.6%, though this figure was close to 40% for some provinces in the southern region of the country.
In Chile, one of the confirmed cases was a healthcare worker who resides in Palena Province, Los Lagos Region, and reported experiencing symptoms on 2 January 2019. The case had a travel history to Epuyén for one day in mid-November, and later hosted and cared for a confirmed case from Epuyén while she was in her prodromal phase. This is the first confirmed case of hantavirus in Los Lagos Region in 2019. During 2018, there were eight cases of hantavirus reported in Chile, including two deaths.
Figure 1. Distribution of confirmed cases of HPS by week of symptom onset in Epuyén, Chubut Province, Argentina.
WHO risk assessment
HPS is a zoonotic, viral respiratory disease. The causative agent belongs to the genus Hantavirus, family Bunyaviridae. The infection is acquired primarily through inhalation of aerosols or contact with infected rodent excreta, droppings, or saliva of infected rodents. Cases of human hantavirus infection usually occur in rural areas (e.g. forests, fields, and farms) where sylvatic rodents hosting the virus might be found and where persons may be exposed to the virus.
This disease is characterized by headache, dizziness, chills fever, myalgia, and gastrointestinal problems, such as nausea, vomiting, diarrhea, and abdominal pain, followed by sudden onset of respiratory distress and hypotension. Symptoms of HPS typically occur from two to four weeks after initial exposure to the virus. However, symptoms may appear as early as one week and as late as eight weeks following exposure. The case-fatality rate can reach 35-50%.
In the Americas, HPS cases have been reported in several countries. Environmental and ecological factors affecting rodent populations can have a seasonal impact on disease trends. Since the reservoir for hantavirus is sylvatic rodents, mainly Sigmodontinae species, transmission can occur when people come in contact with the rodent habitat. Limited human-to-human transmission of HPS due to Andes virus in Argentina has been previously documented. There are no specific evidence-based procedures for HPS patient isolation. Standard precautions1 should always be put in place, as well as rodent control measures.
(Continue . . . .)