Wild Rats, Laboratory Rats, Pet Rats: Global Seoul Hantavirus Disease Revisited

Abstract

Recent reports from Europe and the USA described Seoul orthohantavirus infection in pet rats and their breeders/owners, suggesting the potential emergence of a "new" public health problem. Wild and laboratory rat-induced Seoul infections have, however, been described since the early eighties, due to the omnipresence of the rodent reservoir, the brown rat Rattus norvegicus. Recent studies showed no fundamental differences between the pathogenicity and phylogeny of pet rat-induced Seoul orthohantaviruses and their formerly described wild or laboratory rat counterparts. The paucity of diagnosed Seoul virus-induced disease in the West is in striking contrast to the thousands of cases recorded since the 1980s in the Far East, particularly in China. This review of four continents (Asia, Europe, America, and Africa) puts this "emerging infection" into a historical perspective, concluding there is an urgent need for greater medical awareness of Seoul virus-induced human pathology in many parts of the world Given the mostly milder and atypical clinical presentation, sometimes even with preserved normal kidney function, the importance of simple but repeated urine examination is stressed, since initial but transient proteinuria and microhematuria are rarely lacking.

Keywords: Seoul virus (SEOV); acute kidney injury (AKI); brown rat; hantavirus; hantavirus cardio-pulmonary syndrome (HCPS); hantavirus disease; hemorrhagic fever with renal syndrome (HFRS); laboratory rat; pet rat; wild rat.

Figure 1

The map does not aspire to completeness and refers only to data given in the text. The first SEOV isolation occurred in 1980 in S. Korea [8], followed in 1982 by China [20], and in 1983 by Japan [21]. Whereas China suffered mixed HTNV-SEOV epidemics, involving thousands of cases, each year, laboratory rat-transmitted SEOV outbreaks were an extensive and recurrent problem in several Japanese medical institutions, during the 1970–1980s (see text). The question mark in Sulawesi, Indonesia, refers to a SEOV infection in a German tourist [22], which may, however, have occurred after his return home (see text under “Germany).

Figure 2

The map does not aspire to completeness and refers only to data given in the text. Except for IR461, isolated in 1984 in Porton Down, Salisbury, UK [90], and for the Polle 18 SEOV strain, isolated in 1988 in Germany (Lower Saxony) [91], all other European SEOV isolates are of more recent dates (see text). The first (1978) western human SEOV infections, propagated by laboratory rats, were clinically described in Belgium [92,93], whereas the earliest series of 16 clinically and serologically proven SEOV-HFRS cases, after exposure to wild rats, was documented in County Down, Northern Ireland, UK, 1994 [94]. For the 1983 and 1988 probable isolated SEOV-HFRS cases in Glasgow and elsewhere in the UK, see the Supplementary Table S1 in the review by McElhinney et al. [95].

Figure 3

The map does not aspire to completeness and refers only to data given in the text. The first SEOV isolation from a wharf rat captured in Philadelphia, USA, succeeded in 1984 [9], and was rapidly followed by other isolations from wharf rats in different port cities in North and South America (Belem, Brazil) (see text). The earliest (January 2, 1993) description of eight clinically and serologically documented SEOV-HFRS cases, occurring after local floods in 1990, came from Recife, Brazil [123]. They also constituted the first proof of hantaviral pathogenicity for humans in the New World.

Figure 4

The map does not aspire to completeness and refers only to data given in the text. The first and only SEOV isolations in Africa to date were obtained from wharf rats in Cairo, Egypt, in 1983–1984 [39]. Despite strong evidence since the 1980s for the presence of a SEOV-like agent in humans and/or wild rats in 17 different African countries, no full clinical and serological description of an autochthonous SEOV-HFRS is available so far (see text).