ETIDIOH - NEW

Abstract Middle East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic virus that causes acute respiratory disease after transmission via close contact with camels . In contrast to the incidence of MERS-CoV human infections in the Middle East , MERS-CoV infections in the Horn of Africa have been rarely reported despite the high number of camels and common camel–human interactions in the area. Whether passive cross-sectional sampling misses active human cases is a significant gap in our understanding of MERS-CoV epidemiology and its impact in the Horn of Africa. To address this gap, we conducted a prospective cross-sectional study at Laisamis Catholic Hospital in northern Kenya’s camel pastoralist community . A total of 942 patients with acute respiratory symptoms were enrolled over 18 months (August 2022–February 2024); 54% of these individuals reported frequent contact with camels and consumption of camel products. Testing via reverse transcriptase – polymerase chain reaction ...

Abstract An unprecedented outbreak of Oropouche virus (OROV) is occurring in the Americas, characterized by thousands of confirmed cases and a wide geographical spread, including areas outside the Amazon Basin. Little is known about this neglected arbovirus regarding its pathophysiological aspects and potentially different transmission modes . This study describes the clinical course of a man who returned from a trip to Cuba and presented to our hospital 4 days after the onset of febrile symptoms. The patient was diagnosed with Oropouche fever and was followed for 177 days after the onset of symptoms. We performed a longitudinal investigation of the samples collected from several body sites ( whole blood, serum, urine, and semen ) with the aim of providing further insights into OROV infection dynamics, using the detection of antigenomic RNA as a marker of active viral replication. Clinical samples that were longitudinally collected over the course of OROV infection showed consistently ...

Abstract Recently, cats have emerged as potential incidental hosts for avian and human influenza A viruses (IAVs), including the highly pathogenic avian influenza (HPAI) H5N1 virus. Following an unprecedented outbreak of H5N1 HPAI in cats in Poland in June 2023, we conducted a cross-sectional epidemiological study to assess the seroprevalence of IAV, especially H5Nx , infections in domestic cats. Eight hundred thirty-five serum samples collected in June 2023 were tested using a competitive ELISA for antibodies to IAV nucleoprotein. Positive or doubtful samples were further screened for H5-specific antibodies. The overall seropositivity for IAV was 8.5% (CI 95%: 6.8%, 10.6%; 71/835 cats), and 23/68 IAV-seropositive cats (33.8%) were also seropositive for H5 antigen . Multivariable analysis identified young age (≤8 years) and male sex as significant risk factors for H5 seropositivity, while non-H5-IAV seropositivity was more common in cats aged ≥12 years. These findings suggest different...

Abstract Background :  The experience of the COVID-19 pandemic has differed across continents. We hypothesized that regional differences in SARS-CoV-2 immunity might explain this observation. We therefore established the WWW Consortium in Ghana , W Africa; Jamaica , W Indies ; and W London . Here, we describe the extent to which antibody immunity differs between these geographic locations.  Methods :  The WWW Consortium harmonises across the HERITAGE (Accra, Ghana), WINDFall (Kingston, Jamaica) and Legacy (London, UK) studies, establishing sharing frameworks for samples , metadata, and data; related permissions and oversight; and associated physical and cloud infrastructure. With centralised testing, we performed serological assessments across all three locations at two snapshots in 2024 (April 1st - August 18th; August 19th - December 31st) using high-throughput live virus neutralization and anti-nucleocapsid IgG, including n=763 individuals.  Findings :  We fo...

Abstract The influenza virus neuraminidase (NA) is a promising target for next-generation influenza vaccines but standardized protocols for NA-based serological assays are lacking. Previous studies have demonstrated discordant results from haemagglutination inhibition and live virus microneutralization assays when comparing matched serum and plasma samples . It is therefore important to consider is the choice of serum or plasma samples in assays measuring influenza virus NA-specific antibodies . Here, we compared antibody titres against influenza A and B virus NAs in matched serum and different types of plasma using an enzyme-linked lectin assay (ELLA) and an enzyme-linked immunosorbent assay (ELISA). We observed good correlations between titres determined in serum and different types of plasma. However, there was variable and often poor agreement in the nominal titre values obtained from serum and different kinds of plasma in both ELLA and ELISA, with plasma samples often resulting in...

Abstract Background In Sri Lanka, a high seroprevalence of antibodies against hantaviruses was reported in communities affected by chronic kidney disease of unknown etiology (CKDu). Recently, two rodent-borne hantaviruses , Lanka virus and Anjozorobe virus , were identified in these areas. However, it is unclear which virus is the source of infection in humans, and its pathogenicity is unknown. Methodology/principal findings A total of 181 sera from febrile patients from two CKDu-endemic regions , Girandurukotte and Polonnaruwa, were examined and Lanka virus genome was detected in two IgM-positive febrile patients . Of 76 serum samples from patients with fever of unknown etiology collected during 2016 examined to identify hantavirus genomes, antibodies, and serotypes, 10 were IgG-positive with five of them having IgM also. They were all without clinical features of hemorrhagic fever with renal syndrome , but three patients required treatment in the intensive care unit. A serotyping str...

Abstract Introduction Middle East respiratory syndrome (MERS) is a zoonotic viral respiratory disease caused by the Middle East respiratory syndrome coronavirus (MERS-CoV), associated with severe clinical outcomes and high mortality. Objectives Our study examined the kinetics of anti-MERS-CoV IgM and IgG antibodies during the acute and convalescent phases of infection, focusing on their correlations with clinical variables such as age and viral load. Methods Serum samples were collected from PCR-confirmed MERS-CoV patients (n = 23) during both phases and compared to healthy controls (n = 23) using validated ELISA-based assays. Results IgM levels peaked in the acute phase and declined significantly in the convalescent phase , while IgG levels were sustained and markedly higher during recovery . Correlation analyses revealed positive relationships between antibody levels and patient age (acute IgM: r = 0.56, p < 0.01; convalescent IgG: r = 0.59, p < 0.01) and viral loads (acute IgM...

Abstract We confirmed influenza A virus (IAV) by PCR in serum from 18 cows on 3 affected dairy farms in California, USA . Our findings indicate the presence of viremia and might help explain IAV transmission dynamics and shedding patterns in cows. An understanding of those dynamics could enable development of IAV mitigation strategies. Source: US Centers for Disease Control and Prevention,  https://wwwnc.cdc.gov/eid/article/31/7/25-0134_article ____

Abstract Highly pathogenic avian influenza (HPAI) H5N1 has been a global concern since its emergence in 1997, causing widespread outbreaks in birds and sporadic human infections . The clade 2.3.4.4b H5N1 virus has rapidly expanded across continents, infecting numerous mammalian species . In 2024, it was detected in dairy cattle for the first time in the U.S., along with human cases following exposure . In Canada , the first human case of this avian influenza was reported in a critically ill adolescent in late 2024. No human-to-human transmission has been documented, but concerns persist regarding mutations associated with enhanced virulence and human adaptation . Although seasonal influenza vaccines are not directed against H5N1, studies suggest that pre-existing immunity from prior infections or vaccinations may provide partial protection against severe H5N1 infections through cross-reactive immune response . Given the ongoing circulation of avian influenza and the rise in human infec...

Abstract We tested cross-neutralization against highly pathogenic avian influenza A(H5N1) virus in adults vaccinated with 2021–2023 seasonal quadrivalent influenza vaccine in the United Kingdom. Seasonal quadrivalent influenza vaccines are unlikely to protect vulnerable persons against severe H5N1 disease during widespread transmission. Enhanced measures are needed to protect vulnerable people from H5N1 virus infection. Source: US Centers for Disease Control and Prevention,  https://wwwnc.cdc.gov/eid/article/31/6/24-1796_article ____

Abstract In February 2024, H5N1 highly pathogenic avian influenza viruses (HPAIVs) of clade 2.3.4.4b were first reported in dairy cows in the USA. Subsequent multiple outbreaks on dairy farms and sporadic human infections have raised substantial public health concerns . In the same year, four H5N1 HPAIVs of clade 2.3.4.4b were isolated from ducks and geese in live poultry markets (LPMs) spanning seven provinces in China . Evolutionary analysis demonstrated that these viruses had undergone two genetic reassortments with H5 influenza viruses from wild birds in different countries. Except for 565/H5N1, the other three viruses exhibited over 99% genetic homology with avian-origin H5N1 HPAIVs from South Korea and Japan . Notably, 571/H5N1 demonstrated high replication efficiency in bovine-derived cells , particularly in bovine mammary epithelial (MAC-T) cells, and caused 16.7% (1/6) mortality in mice at a dose of 10⁵ EID₅₀/50 μL, indicating its zoonotic potential . Given the potential cross...

ABSTRACT The highly pathogenic avian influenza virus A(H5N1) clade 2.3.4.4b has caused a human outbreak in North America since March 2024. Here, we conducted a serosurveillance study to determine the risk of A(H5N1) clade 2.3.4.4b (2024 cattle H5N1) to general population. In the initial screening of 180 serum specimens encompassing all age groups, 2.2% (4/180) had detectable neutralizing antibody (nAb) titers against reverse genetics-derived 2024 cattle H5N1, with all collected from older adults aged ≥60 years old. Further screening showed that 4.2% (19/450) of adults aged ≥60 years old had detectable nAb titers against the 2024 cattle H5N1 . 80% (4/5) serum specimens with nAb titer of ≥40 had detectable HI titer, and there was a positive correlation between nAb titer and HA binding (r = 0.3325, 95% confidence interval 0.2477 to 0.4123; P < 0.0001). The nAb titer against seasonal H1N1 virus was 4.2-fold higher for ≥60 years old individuals with detectable H5N1 nAb titer than those ≥...

Abstract We performed serologic surveillance for selected arthropod-borne viruses (arboviruses) in bats and opossums in the Lacandona Rainforest, Chiapas, Mexico , in 2023–2024. Sera were collected from 94 bats of at least 15 species and 43 opossums of three species. The sera were assayed by the plaque reduction neutralization test (PRNT) for antibodies to eight orthoflaviviruses ( dengue viruses 1–4, St. Louis encephalitis virus , T’Ho virus, West Nile virus, and Zika virus ) and one alphavirus (chikungunya virus; CHIKV). Twelve (12.8%) bats and 15 (34.9%) opossums contained orthoflavivirus-specific antibodies . One bat (a Jamaican fruit bat) was seropositive for Zika virus , and 11 bats contained antibodies to an undetermined orthoflavivirus , as did the 15 opossums. All bats and most opossums seropositive for an undetermined orthoflavivirus had low PRNT titers, possibly because they had been infected with another (perhaps unrecognized) orthoflavivirus not included in the PRNTs. Anti...

Summary Background Latin America has been experiencing an Oropouche virus (OROV) outbreak of unprecedented magnitude and spread since 2023–24 for unknown reasons. We aimed to identify risk predictors of and areas at risk for OROV transmission. Methods In this multidisciplinary, laboratory-based, modelling study, we retrospectively tested anonymised serum samples collected between 2001 and 2022 for studies on virus epidemiology and medical diagnostics in Bolivia, Brazil, Colombia, Costa Rica, Ecuador, and Peru with nucleoprotein-based commercial ELISAs for OROV-specific IgG and IgM antibodies. Serum samples positive for IgG from different ecological regions and sampling years were tested against Guaroa virus and two OROV glycoprotein reassortants (Iquitos virus and Madre de Dios virus) via plaque reduction neutralisation testing (PRNT) to validate IgG ELISA specificity and support antigenic cartography. Three OROV strains were included in the neutralisation testing, a Cuban OROV isolate...

Abstract An unprecedented outbreak of a highly pathogenic avian influenza virus, H5 clade 2.3.4.4b, was reported in United States dairy cattle during the spring of 2024. It has now spread to hundreds of herds across multiple states. In humans, antibodies to the hemagglutinin (HA) protein confer the strongest protection against infection. Human herd immunity limits viral spread but also drives the emergence of antigenic variants that escape dominant antibody responses. We used store-bought milk to profile the collective H5N1 antibody response of dairy cattle herds . We detected HA binding antibodies in specific samples from states with recent/ongoing outbreaks. These antibodies present in milk neutralized replicating virus expressing dairy cattle HA and neuraminidase (NA). Despite originating from independent vendors, dairies/plants, geographic regions, and time, antibodies present in these samples are remarkably similar in activity and HA binding specificity. The dominant antibody resp...

{Excerpts} Recent updates Laboratory CDC completed serology testing on blood specimens from close contacts of a child with mild illness in San Francisco who was confirmed to be positive for avian influenza A(H5N1) virus, though, there were no known animal exposures associated with that case.  -- Serology testing was conducted to look for antibodies to influenza A(H5N1) virus in this child, which would indicate recent infection.  -- The child's blood was tested and found to have antibodies to avian influenza A(H5N1) virus.  -- None of the close contacts of the case in San Francisco who were tested had antibodies to avian influenza A(H5N1) virus, which supports the conclusion that none of these close contacts were infected , and that no person-to-person spread occurred among these close contacts.  -- These findings are reassuring. To date, human-to-human transmission of influenza A(H5) virus has not been identified in the United States. CDC has sequenced the virus from...

Abstract Since March 2024, highly pathogenic avian influenza A(H5N1) viruses have caused outbreaks in dairy cattle and poultry in the United States, and they continue to spill over into humans . However, data on human immune response to those viruses is limited. We report neutralizing antibody responses in 2 dairy farm worker H5N1 cases. Source: US Centers for Disease Control and Prevention,  https://wwwnc.cdc.gov/eid/article/31/4/25-0007_article ____

Abstract Reports of human infections with an influenza A(H5N1) clade 2.3.4.4b virus associated with outbreaks in dairy cows in the United States underscore the need to assess the potential cross-protection conferred by existing influenza immunity . We serologically evaluated ferrets previously infected with an influenza A(H1N1)pdm09 virus for cross-reactive antibodies and then challenged 3 months later with either highly pathogenic H5N1 clade 2.3.4.4b or low pathogenicity H7N9 virus . Our results showed that prior influenza A(H1N1)pdm09 virus infection more effectively reduced the replication and transmission of the H5N1 virus than did the H7N9 virus, a finding supported by the presence of group 1 hemagglutinin stalk and N1 neuraminidase antibodies in preimmune ferrets. Our findings suggest that prior influenza A(H1N1)pdm09 virus infection may confer some level of protection against influenza A(H5N1) clade 2.3.4.4.b virus. Source: US Centers for Disease Control and Prevention,  htt...