Hantavirus in Panama: Twenty Years of Epidemiological Surveillance Experience

Abstract

Twenty years have passed since the emergence of hantavirus zoonosis in Panama at the beginning of this millennium. We provide an overview of epidemiological surveillance of hantavirus disease (hantavirus pulmonary syndrome and hantavirus fever) during the period 1999–2019 by including all reported and confirmed cases according to the case definition established by the health authority. Our findings reveal that hantavirus disease is a low-frequency disease, affecting primarily young people, with a relatively low case-fatality rate compared to other hantaviruses in the Americas (e.g., ANDV and SNV). It presents an annual variation with peaks every 4–5 years and an interannual variation influenced by agricultural activities. Hantavirus disease is endemic in about 27% of Panama, which corresponds to agroecological conditions that favor the population dynamics of the rodent host, Oligoryzomys costaricensis and the virus (Choclo orthohantavirus) responsible for hantavirus disease. However, this does not rule out the existence of other endemic areas to be characterized. Undoubtedly, decentralization of the laboratory test and dissemination of evidence-based surveillance guidelines and regulations have standardized and improved diagnosis, notification at the level of the primary care system, and management in intensive care units nationwide.

Choclo virus (CHOV) recovered from deep metatranscriptomics of archived museum tissues

“…The strains from the province of Panamá form a well-supported clade demonstrating potential geographic substructure (Fig 4) which is congruent with previous findings [39]. More sequencing is needed to determine how closely these are related to clinical strains; however, only seven Panamá residents have reported HCPS in the last 20 years (1% of all cases) [12]. Five other sequences from Panamanian hantaviruses were isolated from the short-tailed cane mouse (Zygodontomys brevicauda) and the Chiriqui harvest mouse (Reithrodontomys creper), but these are likely representative of other hantaviruses (i.e., Calabazo virus and Rio Segundo virus) that have yet to be fully sequenced [44] or associated with human disease (Fig S2).…”

“…An outbreak from late 1999 to early 2000 of hantavirus cardiopulmonary syndrome (HCPS) in western Panama [9,10] has spurred over two decades of epidemiological and wildlife surveillance [12,39]. During those 20 years 712 clinical cases of HCPS were reported in Panama [12] and >11,000 specimens of non-volant mammals with archived biological materials were contributed to museum repositories (https://arctos.database.museum/). Of these, just shy of 800 rodents have been currently screened for prior hantavirus infection using an IgG strip immunoblot assay [40] with an average seropositivity of 16% [39].…”

“…CHOV-associated disease generally has a lower case fatality rate (mean 12.4%, range from 7.3% to 50.0%) than other New World Hantaviruses, but unfortunately predominantly affects young people (ages 20-49) [12].…”

Choclo virus (CHOV) recovered from deep metatranscriptomics of archived frozen tissues in natural history biorepositories

“…Both clinical and rodent CHOV strains were captured from Los Santos, Veraguas, and Coclé provinces; however, only rodent-acquired sequences were found in Panamá ( Fig 3 ). This is reflective of the clinical disease burden with the greatest number of cases in Los Santos (77%) followed by Veraguas (12%) and Coclé (7%) [ 12 ]. However, it should be noted that locations of clinical cases are by residence, and it is possible patients were exposed while traveling to another endemic area of the country.…”

“…From 2001 to 2007 multiple community-wide surveys of western Panamanians without reported HCPS symptomology found 16–60% of the individuals were hantavirus seropositive depending on region [ 14 ], documenting that many mild or asymptomatic exposures were not accounted for in clinical case count data. CHOV-associated disease generally has a lower case fatality rate (mean 7.9%, range from 3% to 50.0%) than other New World Hantaviruses, but unfortunately predominantly affects young people (ages 20–49) [ 12 ].…”