Serological #Evidence of #Flavivirus #Infection Among #Mothers of #Newborns in El Paso, #Texas

 

Abstract

Background: 

Flaviviruses represent a significant worldwide threat to human health and have the potential to emerge and cause outbreaks in non-endemic geographical regions. Ongoing surveillance for these viruses in the United States–Mexican border communities such as El Paso, Texas, is lacking. As a continuing effort to better understand the prevalence and to determine which arboviruses are endemic, the aim of this study was to determine the prevalence rate of specific flavivirus antibody among 910 human umbilical cord blood samples obtained from mothers who delivered newborns in El Paso, Texas.

Materials and Methods: 

The samples were screened for West Nile virus (WNV) and dengue virus (DENV) IgG antibodies with an enzyme-linked immunosorbent assay and confirmed by a plaque reduction neutralization test for DENV, WNV, Zika virus (ZIKV) and Saint Louis encephalitis virus (SLEV).

Results: 

Among the 910 samples, 2% were positive for specific IgG antibody to DENV, 4.4% to WNV, 0.1% to SLEV, and 0.0% for ZIKV antibody. The results confirmed the local transmission of WNV and supported a low prevalence rate for DENV, and this was the first reported serological evidence of SLEV infection in the El Paso community.

Conclusion: 

The interpretation of the public health significance of these observations supported previous findings of ongoing transmission of WNV and suggested the possibility of DENV transmission and re-emergence of SLEV in the community. Therefore, prospective studies are needed to obtain a more conclusive understanding of the prevalence of flaviviruses in the El Paso community.

Source: Vector-Borne and Zoonotic Diseases, https://www.liebertpub.com/doi/abs/10.1177/15303667251367518

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#Phylogenetic analysis of #H5N1 #influenza viruses isolated from dairy #cattle in #Texas in December 2024

LETTER

Highly pathogenic avian influenza (HPAI) viruses of genotype B3.13 were first reported in dairy cattle in March 2024 and, by 4 March 2025, had infected at least 989 cattle herds in 17 states in the US (https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/hpai-confirmed-cases-livestock; accessed on March 24, 2025). Importantly, spillover infections of poultry and mammalian species, including cats and humans, have occurred (https://www.cdc.gov/bird-flu/situation-summary/index.html; accessed on 4 March 2025). Texas reported several infected herds in the spring (1) and early summer of 2024 but saw fewer outbreaks during the second half of 2024, with reported outbreaks in July and December (2). Since September 2024, almost all reported outbreaks of genotype B3.13 viruses in dairy cattle have occurred in California. Here, we characterized self-submitted samples from a farm in Texas that experienced an outbreak in December 2024. This farm had purchased dairy cattle from several states in the US. We, therefore, asked whether the December 2024 outbreak in Texas was caused by B3.13 viruses that circulated undetected in dairy cattle or other species in Texas or resulted from the introduction of B3.13 viruses from California (having the highest number of affected farms at that time) or other states.

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Source: Journal of Virology, https://journals.asm.org/doi/full/10.1128/jvi.00580-25?af=R

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Detection of #Measles in #Texas #Wastewater

Abstract

Measles outbreaks continue to pose significant public health challenges globally despite the availability of effective vaccines. In this study, we evaluated wastewater-based surveillance for detection of measles virus during an ongoing outbreak in Texas. Weekly wastewater samples collected from two Texas cities between January 2 and March 17, 2025 were analyzed using multiple RT-PCR assays targeting the nucleoprotein and matrix genes of the measles virus. Viral RNA was detected in multiple days from both cities, with City A showing positives from January 13 and City B from January 6, both predating the first confirmed case in the state on January 23. Sequencing of PCR amplicons confirmed the specificity of detection and phylogenetic analysis using global and U.S. measles genome databases further validated that the viral RNA belonged to the currently circulating genotype D8. Our findings demonstrate that wastewater surveillance can provide early evidence of measles virus circulation in communities before clinical cases are recognized and can support public health responses to these re-emerging infectious diseases.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.04.08.25325475v1

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Superior #replication, #pathogenicity, and immune #evasion of a #Texas dairy #cattle #H5N1 virus compared to a historical avian isolate

Abstract

The current outbreak of highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype clade 2.3.4.4b in dairy cattle in the United States has affected nearly 900 dairy farms and resulted in at least 39 human infections, putting health authorities and the scientific community on high alert. Here we characterize the virus growth properties and host-pathogen interactions of an isolate obtained from a sick dairy cow in Texas in vitro and in vivo and compare it to an older HPAI isolate. Despite so far being associated with mild disease in human patients, the cattle H5N1 virus showed superior growth capability and rapid replication kinetics in a panel of human lung cell lines in vitro. In vivo, cattle H5N1 exhibited more intense pathogenicity in mice, with rapid lung pathology and high virus titers in the brain, accompanied by high mortality after challenge via different inoculation routes. Additionally, the cattle H5N1 demonstrated efficient antagonism of overexpressed RIG-I- and MDA5-mediated innate antiviral signaling pathways. In summary, this study demonstrates the profound pathogenicity and suggests a potential innate immune escape mechanism of the H5N1 virus isolated from a dairy cow in Texas.

Source: Scientific Reports, https://www.nature.com/articles/s41598-025-93493-5

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Identification of Aminoacid #Residues Responsible for Differential #Replication & #Pathogenicity of Avian #Influenza Virus #H5N1 Isolated from #Human & #Cattle in #Texas

Abstract

Highly pathogenic avian influenza viruses (HPAIV) pose a serious public health concern. In March 2024, a first-time outbreak of HPAIV H5N1 in dairy cattle herds was reported in the United States (US). Since then, the virus has continued to spread in cattle herds and spilt over into humans. We recently showed that the first human isolate reported in the US in Texas (HPhTX) from a dairy worker in an affected cattle farm has enhanced replication kinetics and pathogenicity in mice compared to a closely related bovine isolate (HPbTX). However, the molecular determinants of differential pathogenicity have not yet been identified. Herein, we show that HPhTX has enhanced polymerase activity, compared with HPbTX, in human cells and that the polymerase basic 2 (PB2) protein is the main factor responsible for this difference. Through single and combined site-directed mutagenesis and swapping the three amino acids different between HPhTX and HPbTX, we found that PB2 mutation E627K is the major contributor to the enhanced polymerase activity of HPhTX. E362G substitution in HPhTX PB2 affected the polymerase, although to a lesser extent than E627K. Moreover, M631L mutation in HPhTX PB2 enhanced polymerase activity. Rescue of a loss-of-function recombinant HPhTX (rHPhTX) containing mutations at residues 627 and 362, alone or in combination, revealed a contribution of PB2 E362G and K627E in morbidity, mortality, and viral replication as compared to rHPhTX wild-type (WT), and significantly reduced viral pathogenicity to levels comparable to rHPbTX WT. These findings indicate that HPAIV H5N1 of cattle origin isolated from the first human case has post-transmission amino acid changes that increase viral replication in human cells and pathogenicity in mice.

Source: BioRxIV, https://www.biorxiv.org/content/10.1101/2025.03.01.640810v1

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#USA, #Texas announces first #death in #measles #outbreak

The Texas Department of State Health Services is reporting the first death from measles in the ongoing outbreak in the South Plains and Panhandle regions. 

The school-aged child who was not vaccinated was hospitalized in Lubbock last week and tested positive for measles.

As of Feb. 25, 124 cases of measles have been confirmed in the outbreak since late January. Most of the cases are in children. Eighteen people have been hospitalized over the course of the outbreak.

Measles is a highly contagious respiratory illness, which can cause life-threatening illness to anyone who is not protected against the virus. During a measles outbreak, about one in five people who get sick will need hospital care and one in 20 will develop pneumonia. Rarely, measles can lead to swelling of the brain and death. It can also cause pregnancy complications, such as premature birth and babies with low birth weight.

Measles can be transmitted by direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs, or sneezes. People who are infected will begin to have symptoms within a week or two after being exposed. Early symptoms include high fever, cough, runny nose, and red, watery eyes. A few days later, the telltale rash breaks out as flat, red spots on the face and then spreads down the neck and trunk to the rest of the body. A person is contagious about four days before the rash appears to four days after. People who could have measles should stay home during that period.

People who think they have measles or may have been exposed to measles should isolate themselves and call their health care provider before arriving to be tested. It is important to let the provider know that the patient may have measles and to get instructions on how to come to the office for diagnosis without exposing other people to the virus.

The best way to prevent getting sick is to be immunized with two doses of a measles-containing vaccine, which is primarily administered as the combination measles-mumps-rubella or MMR vaccine. Two doses of the MMR vaccine prevent more than 97 percent of measles infections. A small number of vaccinated people can occasionally develop measles. In these cases, the symptoms are generally milder, and they are less likely to spread the disease to other people. DSHS and the Centers for Disease Control and Prevention recommend children receive one dose of MMR at 12 to 15 months of age and another at 4 to 6 years. Children too young to be vaccinated are more likely to have severe complications if they get infected with the measles virus. However, each MMR dose lowers the risk of infection and the severity of illness if infected.

Health care providers can find recommendations for infection control and diagnostic testing in DSHS health alerts. Providers should report any suspected cases to their local health department immediately, preferably while the patient is still with the provider.

DSHS posts additional information about the outbreak cases on the News & Alerts page on Tuesdays and Fridays.

Source: Department of Health, https://www.dshs.texas.gov/news-alerts/texas-announces-first-death-measles-outbreak

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#Replication kinetics, #pathogenicity and virus-induced cellular responses of #cattle-origin #influenza A(#H5N1) isolates from #Texas, #USA

ABSTRACT

The host range of HPAIV H5N1 was recently expanded to include ruminants, particularly dairy cattle in the United States (US). Shortly after, human H5N1 infection was reported in a dairy worker in Texas following exposure to infected cattle. Herein, we rescued the cattle-origin influenza A/bovine/Texas/24-029328-02/2024(H5N1, rHPbTX) and A/Texas/37/2024(H5N1, rHPhTX) viruses, identified in dairy cattle and human, respectively, and their low pathogenic forms, rLPbTX and rLPhTX, with monobasic HA cleavage sites. Intriguingly, rHPhTX replicated more efficiently than rHPbTX in mammalian and avian cells. Still, variations in the PA and NA proteins didn’t affect their antiviral susceptibility to PA and NA inhibitors. Unlike rHPbTX and rLPbTX, both rHPhTX and rLPhTX exhibited higher pathogenicity and efficient replication in infected C57BL/6J mice. The lungs of rHPhTX-infected mice produced higher inflammatory cytokines/chemokines than rHPbTX-infected mice. Our results highlight the potential risk of HPAIV H5N1 virus adaptation in human and/or dairy cattle during the current multistate/multispecies outbreak in the US.

Source: Emerging Microbes and Infection, https://www.tandfonline.com/doi/full/10.1080/22221751.2024.2447614

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