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Biological Health Hazard – Pestilence, Leptospirosis (Rats): New York City


Environmental Health Hazard  – Pestilence

North America- USA | State of New York, New York City
Bio-hazard Level: Hazardous
Location: 40°42’46.0″N 74°00’21.4″W

Published Date: 2017-02-19 14:37:40
Subject: PRO/AH/EDR> Leptospirosis – USA (02): (NYC) fatal, rats, comment
Archive Number: 20170219.4850304

Date: Sat 18 Feb 2017
From: Jan Clement <> [edited]

Re: ProMED-mail post Leptospirosis – USA: (NYC) fatal, living in rat-infested buildings Archive Number: 20170215.4841814
After the discovery of 3 cases (of which one fatal) of rat-transmitted leptospirosis in the Bronx, New-York City, it is perhaps appropriate to remember that the infectious disease mimicking leptospirosis almost to perfection is hantavirus-induced “hemorrhagic fever with renal syndrome” (HFRS).

Both infections have surprisingly many similarities, despite their completely different etiology. Both are zoonoses with a worldwide distribution, both are spread uniquely (hantavirus) or mainly (leptospirosis) by wild rodents, and hence have even some epidemiological similarities, such as outbreaks after floods due to heavy rainfalls. Symptoms of leptospirosis can overlap almost completely those of hantavirus infections: fever, myalgia, headache, and liver involvement with jaundice from 12 percent up to 93 percent of the cases, constituting together with thrombocytopenic acute kidney injury (AKI) the classic form of Weil’s disease, the most severe variant of leptospirosis.

However, (mostly mild) icterus can be found in some HFRS cases as well, so this triad in a patient with fever is not always exclusive for the diagnosis of Weil’s disease. Even more confusing, all major complications of leptospirosis, such as acute respiratory failure, hemorrhages, rhabdomyolysis, and extreme thrombocytopenia, with or without overt signs of diffuse intravascular coagulation (DIC), can be encountered in hantavirus infections as well, and act as a severity index of the degree of AKI to come in both conditions. Even the renal lesions in leptospirosis are quite similar to hantavirus nephropathy: interstitial edema and infiltrates, sometimes complicated by acute tubular necrosis and /or medullar hemorrhages.

Nevertheless, a rapid distinction between the 2 entities is of paramount importance, since leptospirosis can be successfully treated in the early phase with antibiotics. (ProMED-mail post Leptospirosis – Jamaica (02) Archive Number: 20071018.3409)(Clement J. Acute kidney injury and hantavirus disease. In: Oxford Textbook of Clinical Nephrology (OTCN), 4th edition. Ed. Turner N, Lameire N, Goldsmith D, Winearls C, Himmelfarb J, Remuzzi G. Oxford University Press, Oxford, UK, 2015: pp. 2059-2066. ISBN-13:978-0199592548).

The hantavirus species spread worldwide by the wild rat is known since 1982 as Seoul virus (SEOV). Of interest, SEOV was recently characterized by quantitative RT-PCR in New-York City (NYC) wharf rats, called Baxter virus, and suggested as being recently introduced in the NYC port by international trade, and “thus constituting a new potential risk for human health in the city” (ProMED-mail post Hantavirus update – Americas (41): USA (NYC) Seoul virus, rat reservoir Archive Number: 20141017.2872156). However, in view of the historical fact that NYC was already the 6th major port city in the USA where SEOV had been found in local wharf rats since 1982, and because of genomic sequence comparisons, this hypothesis was later questioned (ProMED-mail post Hantavirus update – Americas (42): USA (NY) Seoul virus, rat reservoir, comment Archive Number: 20141028.2907225) (Clement J, Maes P, Van Ranst M. Hemorrhagic fever with renal syndrome in the new, and Hantavirus Pulmonary Syndrome in the old world: Paradi(se)gm lost or regained? Virus Res. 2014:187:55-58. doi: 10.1016/j.virusres.2013.12.036.

On the other hand, after decades of scientific lack of interest, and despite the fact that the 1st pathogenic hantavirus isolated in the New World was in fact a SEOV (Girard Point virus, isolated in 1984 from a Philadelphia wharf rat), the concept that SEOV-induced HFRS was a novel entity indeed, to be reckoned with in the New World, was finally accepted after a recent 2017 outbreak of “SEOV-nephropathy”, both in Illinois and in Wisconsin (ProMED-mail post Hantavirus update – Americas (05): USA (IL,WI) Seoul virus Archive Number: 20170122.4782661).

Moreover, lab confirmation of a recent leptospira infection in cases of thrombocytopenic AKI does not exclude a dual, concomitant infection with a hantavirus, most probably a SEOV when wild rats are involved. This underestimated possibility was demonstrated in a prospective study in Sri Lanka, a country highly endemic for leptospirosis (Sunil-Chandra NP, Clement J, Maes P, de Silva HJ, Van Esbroeck M, Van Ranst M. Concomitant leptospirosis-hantavirus co-infection in acute patients hospitalized in Sri Lanka: implications for a potentially worldwide underestimated problem. ERRATUM. Epidemiol Inf 2015;143(10):2094. doi:, and confirmed in a retrospective study in Belgium, a country with a low leptospirosis endemicity, like the USA (Clement J, Van Esbroeck M, Lagrou K, Verschueren J, Sunil-Chandra NP, Van Ranst M. Letter to the Editor: Leptospirosis versus hantavirus infections in the Netherlands and in Belgium, 2000 to 2014. Euro Surveill. 2014;19(38):pii=20912. Available online:

If not too late, a search for SEOV co-infection in the current 3 Bronx leptospirosis cases would be highly interesting, as would be the demonstration of SEOV and leptospira co-infection in the suspected local NYC rats.

Communicated by:
Jan Clement, Katrien Lagrou, Marc Van Ranst
Hantavirus NRC,
University Hospital Gasthuisberg,
Leuven, Belgium.
Marjan Van Esbroeck,
Leptospirosis NRC,
Institute of Tropical Medicine,
Antwerp, Belgium.

[ProMED-mail thanks Dr Jan Clement and colleagues for their continued contributions to the discussion of leptospirosis and hantavirus infection. – Mod.ML

A HealthMap/ProMED-mail map can be accessed at:]

See Also

Leptospirosis – USA: (NYC) fatal, living in rat-infested buildings 20170215.4841814
Hantavirus update – Americas (05): USA (IL,WI) Seoul virus 20170122.4782661

Hantavirus update – Americas (42): USA (NY) Seoul virus, rat reservoir, comment 20141028.2907225
Hantavirus update – Americas (41): USA (NYC) Seoul virus, rat reservoir 20141017.287215

Leptospirosis – Jamaica (02) 20071018.3409

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ProMED-mail is a program of the International Society for Infectious Diseases

RelatedParasites and Pestilence. It has interactive maps you can click to see which parasites are found where.

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