Routine Puumala virus (PUUV) infection diagnosis is performed using serological commercial kits of which performances have not been established in real life, which use recombinant protein from strains from Central or North Europe. Molecular diagnostic of these infection is not the rule. Consequently the objectives of the project are to evaluate the performances of the serological commercial assays in real life in France and to assess the use of urine versus plasma for the molecular diagnostic of this infection.

Hantaviruses constitute one of the 5 genera in the family Bunyaviridae and are associated with several natural host species including rodents, insectivores and bats. Infection of these species remains unapparent. Transmission of the virus between individuals occurs through direct contact or through inhalation of saliva, feces, or urine. Using these routes, some rodent-borne hantaviruses can be transmitted to humans and cause hemorrhagic fever with renal syndrome or cardiopulmonary syndrome. Human-to-human transmission is rare. There is no specific treatment. Inactivated vaccines against Hantaan and Seoul (SEOV) viruses are only available and licensed in China and South Korea.

Puumala (PUUV), SEOV, Tula and Nova hantaviruses are reported in metropolitan France but only the 2 first are of medical importance. One single human SEOV infection has been confirmed and very few cases have been suspected. In contrast, about 100 PUUV human cases are detected yearly and occurred in the North East quarter of France.

Routine PUUV infection diagnosis is performed using serological commercial kits, allowing detection of IgM or IgG against PUUV or other hantaviruses. The performances (sensitivity and specificity) of these tests as reported by the manufacturers are very good. However, 1/ they have been established with panels of reference sera and not in real life for all assays but one; 2/ these assays are based on N recombinant protein but it has been reported that using whole virus antigens, instead of the single N protein, detection of IgG against hantavirus would be earlier; 3/ PUUV strains used to produce the recombinant N proteins are phylogenetically far from the strains detected in France, and the use of a Belgian strain close to the French strains (instead of a Scandinavian strain) since 1990 has improved the performances of the Institut Pasteur, Hantavirus National Reference Center, home-made assays.

Molecular diagnosis is not performed routinely and only 3 very recent studies reported data on PUUV viremia, using blood, plasma or sera. Urine samples previously showed to be a good alternative for PUUV detection but the use if this type of sample has not been evaluated in real life and the viruria not studied.

The performances of most of the commercial immunoassays for the detection of antibodies against hantaviruses, especially PUUV, has not yet been reported when used in real life.

The investigators propose to perform this evaluation for 9 assays, some of them now being used for the last few years by 13 French clinical laboratories:

• Euroimmun AG : Hantavirus Pool 1 " Eurasia " IgM and IgG ELISA
• Focus Diagnostics Hantavirus DxSelect IgM and IgG ELISA
• Progen Hantavirus (Puumala) IgM and IgG ELISA
• Reagena Puumala IgM and IgG EIA
• Reagena Reascan Puumala IgM (rapid test)

Furthermore, they will explore the use of urine as a sample type for molecular diagnostics. Hantaviruses are excreted in the urine of rodents and have been detected in a few studies in the urine of patients, as well as IgG and IgM against hantaviruses. The shedding of the virus may be higher and/or longer in the urine than in plasma. Viruria compared to viremia has never been reported.

The results of the study will allow the recommendation of some commercial assays to be used at admission of patients for the serological diagnosis of PUUV infection.

Furthermore, the results of the study, assessing the use of the urine versus blood for the molecular detection of PUUV, may recommend the use of the molecular techniques for the diagnostic of this infection.

Inclusion Criteria:

Hospitalized patients, male or female, more than 18 years old and less than 76 years old1:

• having at admission or within 8 days preceding admission a pain , a documented febrile syndrome (body temperature ≥ 38°C) and a platelet count < 150 G/L,
• exposed to PUUV infection (for the last 6 weeks) or living in a French municipality where Hantavirus infection cases have been recorded during the 2003-2013 period or in a municipality bordering one of them ,
• giving their written consent after being informed of the research and the collection of data, and blood & urine samples.

NB: persons in emergency situation will be proposed to participate because their situation may affect the performances of laboratory diagnostics.

Exclusion Criteria:

Hospitalized patients:

• who are known to have been previously diagnosed infected by an hantavirus (medical records and/or laboratory results),
• who are known to present stable thrombocytopenia,
• who, according to the medical staff, would not adhere to the protocol,
• for whom the health status, according to the medical staff, may interfere with the study or is not compatible with the sampling planned in the study.

NB: Pregnant, parturient or breast-feeding women as well as patients under psychiatric care or patients subject to a legal protection order will be not proposed to participate.

Patients hospitalized for suspected PUUV infection