Project description:To ascertain the presence of West Nile virus (WNV), we sampled mosquitoes in 2006 in locations in southern Spain where humans had been infected. WNV genomic RNA was detected in 1 pool from unfed female Culex pipiens mosquitoes. Phylogenetic analysis demonstrated that this sequence cannot be assigned to previously described lineages of WNV.

| S-EPMC3322021 | biostudies-literature

Imported Human West Nile Virus Lineage 2 Infection in Spain: Neurological and Gastrointestinal Complications.

Project description:We report the first human case of West Nile virus (WNV) lineage 2 infection imported to Spain by a traveler returning from Romania. Serum, cerebrospinal fluid and urine samples were analyzed and West Nile virus infection was identified by PCR and serological tests. The patient developed fever, diarrhea and neurological symptoms, accompanied by mild pancreatitis, described previously in very few cases as a complication of WNV infection and by alithiasic cholecystitis. Viral RNA was detected in urine until 30 days after the onset of symptoms and neutralizing antibodies were detected at very low titers. The phylogenetic analysis in a fragment of the NS5 gene of the virus showed a homology with sequences from WNV lineage 2 belonging to the monophyletic Central/Southern European group.

| S-EPMC7077332 | biostudies-literature

West Nile virus infection of birds, Mexico.

Project description:West Nile virus (WNV) has caused disease in humans, equids, and birds at lower frequency in Mexico than in the United States. We hypothesized that the seemingly reduced virulence in Mexico was caused by attenuation of the Tabasco strain from southeastern Mexico, resulting in lower viremia than that caused by the Tecate strain from the more northern location of Baja California. During 2006-2008, we tested this hypothesis in candidate avian amplifying hosts: domestic chickens, rock pigeons, house sparrows, great-tailed grackles, and clay-colored thrushes. Only great-tailed grackles and house sparrows were competent amplifying hosts for both strains, and deaths occurred in each species. Tecate strain viremia levels were higher for thrushes. Both strains produced low-level viremia in pigeons and chickens. Our results suggest that certain avian hosts within Mexico are competent for efficient amplification of both northern and southern WNV strains and that both strains likely contribute to bird deaths.

| S-EPMC3311203 | biostudies-literature

A Mouse Model of Chronic West Nile Virus Infection

Project description:Here, we characterize the RIX line CC(032x013)F1, which serves as a mouse model of chronic WNV infection. While studies using C57BL/6 mice have shown that WNV RNA can persist in the CNS up to 3 months post infection in a limited fraction of mice (Appler et al., 2010), to date there is a lack of a robust mouse model of chronic West Nile virus infection that can be used to elucidate the immune responses associated with this viral persistence and chronicity of symptoms described in human patients. Here, we characterize this line in comparison with lines showing either no disease symptoms or significant disease, and suggest a mechanism by which WNV infection can become chronic through alterations in immune responses.

2016-06-01 | GSE82046 | GEO

Unprecedented increase of West Nile virus neuroinvasive disease, Spain, summer 2020.

Project description:Cases of West Nile neuroinvasive disease (WNND) in Spain increased in summer 2020. Here we report on this increase and the local, regional and national public health measures taken in response. We analysed data from regional surveillance networks and the National Epidemiological Surveillance Network, both for human and animal West Nile virus (WNV) infection. During the 2020 season, a total of 77 human cases of WNV infection (median age 65 years; 60% males) were detected in the south-west of Spain; 72 (94%) of these cases developed WNND, presenting as meningoencephalitis, seven of which were fatal. In the previous two decades, only six human cases of WNND were detected in Spain. Reduced activities for vector control this season, together with other factors, might have contributed to the massive increase. Public health measures including vector control, campaigns to raise awareness among physicians and the general population, and interventions to ensure the safety of donations of blood products, organs, cells and tissues were effective to reduce transmission. Going forward, maintenance of vector control activities and an update of the vector-borne diseases response plan in Spain is needed.

| S-EPMC8120797 | biostudies-literature