Emergence of a novel #reassortant highly pathogenic avian #influenza clade 2.3.4.4b A(#H5N2) Virus, 2024

ABSTRACT

Reassortant highly pathogenic avian influenza A(H5N2) clade 2.3.4.4.b viruses were detected from ducks and environmental samples in Egypt, June 2024. Genomic and phylogenetic analyses revealed a novel genotype produced by the reassortment of an A(H5N1) clade 2.3.3.4b virus with an A(H9N2) G1-like virus. Monitoring the spread of this virus is important.

Source: Emerging Microbes and Infections, https://www.tandfonline.com/doi/full/10.1080/22221751.2025.2455601#abstract

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No #Evidence of Anti - #influenza #Nucleoprotein #Antibodies in Retail #Milk from Across #Canada (April to July 2024)

Abstract

Following reports of HPAI H5N1 infections of dairy cattle in the United States (US) in March 2024, we established a Pan-Canadian Milk network to monitor retail milk in Canada. Milk samples from across Canada that had previously tested negative for influenza A virus (IAV) RNA were tested for the presence of anti-IAV nucleoprotein (NP) antibodies, as an indicator of past infection of dairy cattle. None of the 109 milk samples tested had evidence of anti-IAV NP antibodies. This is consistent with previous findings from our academic group as well as others including federal testing initiatives that have not found any IAV RNA in milk. Although not surprising given that no cases of H5N1 in cattle have been reported in Canada to date, this work further supports that the extensive outbreak in dairy cattle in the US has not extended northward into Canada, and the integrity of the Canadian milk supply remains intact.

Source: MedRxIV, https://www.medrxiv.org/content/10.1101/2025.01.31.25321461v1

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Intraductal #infection with #H5N1 clade 2.3.4.4b #influenza virus

LETTER

In March 2024, highly pathogenic avian influenza (HPAI) H5N1 of the clade 2.3.4.4b was detected in dairy cows in Texas and has since been detected in several other U.S. states (1). Virus has been detected within cow’s milk, indicating that the mammary epithelium may support viral replication (2). Virus has also been detected on milking machines, leading to a hypothesis that influenza is spreading through fomites from udder to udder instead of the intranasal route (3, 4). There have been studies using cows to better understand mammary infections; however, the cow model is costly and limited (1, 5). We sought to establish a model for intramammary infections of H5N1 and H1N1 influenza virus in mice.

(...)

Source: Journal of Virology, https://journals.asm.org/doi/full/10.1128/jvi.01927-24?af=R

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Monitoring for Avian #Influenza A(#H5) Virus In #Wastewater, January 19-25 2025

{Excerpt}

Time Period: January 19 - January 25, 2025

-- H5 Detection: 33 sites (10.1%)

-- No Detection: 295 sites (89.9%)

-- No samples in last week: 61 sites

(...)

Source: US Centers for Disease Control and Prevention, https://www.cdc.gov/bird-flu/h5-monitoring/index.html

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#Panama - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

The laboratory diagnosed type H5 on Thursday, January 23 in one of the sick birds that was sampled in the framework of passive surveillance, on January 24 all birds were culled, on January 29 the laboratory confirmed the detection of Neuraminidase 1 and identification of hemagglutinin genes found in the cleavage site of avian influenza virus type A lineage Goose/Guangdong (Gs/GD) subtype H5, clade 2.3.4.4. highly pathogenic.

Out of the 408 backyard birds, one died and two became sick in Chiriquí Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6225

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#Hungary - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification, 2nd

A  foie gras goose holding in Heves Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6227

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#Hungary - High pathogenicity avian #influenza #H5N1 viruses (#poultry) (Inf. with) - Immediate notification

 A breeding goose holding in Pest Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6228

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#Finland - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

 A wild Eurasian Jackdaw in Lounais-Suomen aluehallintovirasto Region.

Source: WOAH, https://wahis.woah.org/#/in-review/6229

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#Mexico’s Laboratory-Confirmed #Human Case of #Infection with the #Influenza A(#H5N2) Virus

Abstract

In April 2024, the Instituto Nacional de Enfermedades Respiratorias of Mexico City identified a case of unsubtypeable Influenza A in a 58-year-old immunocompromised patient with renal failure due to diabetic nephropathy and bacterial peritonitis. Through sequencing the M, NS, NA, NP, and HA complete segments, we identified an H5N2 influenza virus with identity of 99% with avian influenza A(H5N2) from Texcoco, Mexico, in 2024. This case is the first reported with direct evidence of human infection caused by the H5N2 influenza virus; the relationship of the virus with the severity of his condition remains unknown.

Source: Viruses, https://www.mdpi.com/1999-4915/17/2/205

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Suspected and confirmed #mpox cases in #DRC: a retrospective #analysis of national epidemiological and laboratory #surveillance data, 2010–23

Summary

Background

DR Congo has the highest global burden of mpox, a disease caused by infection with the monkeypox virus. The incidence has risen since 1980, but recent analyses of epidemiological trends are lacking. We aimed to describe trends in suspected and confirmed mpox cases in DR Congo using epidemiological and laboratory mpox surveillance data collected from 2010 to 2023, and provide insights that can better inform the targeting and monitoring of control strategies.

Methods

We analysed aggregated national epidemiological surveillance data and individual-level laboratory data from 2010 to 2023. We calculated incidence based on suspected cases, case-fatality ratios, and percentage of laboratory-confirmed cases and assessed geospatial trends. Demographic and seasonal trends were investigated using generalised additive mixed models.

Findings

Between Jan 1, 2010, and Dec 31, 2023, a total of 60 967 suspected cases and 1798 suspected deaths from mpox were reported in DR Congo (case-fatality ratio 2·9%). The number of reporting provinces increased from 18 of 26 provinces in 2010 to 24 of 26 provinces in 2023. The annual incidence increased from 2·97 per 100 000 in 2010 to 11·46 per 100 000 in 2023. The highest incidence (46·38 per 100 000) and case-fatality ratio (6·0%) were observed in children younger than 5 years. Incidence was higher in rural compared with urban areas. PCR testing was performed for 7438 suspected cases (12·2%), with 4248 (57·1%) of 7438 samples testing positive. Median age of confirmed cases (13·0 years [IQR 6·0–25·0]) remained stable, although the 95th percentile of age increased over time.

Interpretation

The incidence and geographical distribution of suspected mpox cases have increased substantially since 2010. Improvements in surveillance and decentralised testing are essential to monitor mpox trends and direct interventions effectively, to address the public health emergency declarations issued in August, 2024.

Funding

Belgian Directorate-General Development Cooperation and Humanitarian Aid; European and Developing Countries Clinical Trials Partnership; Research Foundation–Flanders; European Civil Protection and Humanitarian Aid Operations; Department of Economy, Science, and Innovation of the Flemish Government; Canadian Institutes of Health Research; and the International Development Research Centre.

Source: Lancet, https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(24)02669-2/abstract?rss=yes

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Structure of a #zoonotic #H5N1 #hemagglutinin reveals a #receptor-binding site occupied by an auto-glycan

Summary

Highly pathogenic avian influenza has spilled into many mammals, most notably cows and poultry, with several dozen human breakthrough infections. Zoonotic crossovers, with hemagglutinins mutated to enhance viral ability to use human α2-6-linked sialic acid receptors versus avian α2-3-linked ones, highlight the pandemic risk. To gain insight into these crossovers, we determined the cryoelectron microscopy (cryo-EM) structure of the hemagglutinin from the zoonotic H5N1 A/Texas/37/2024 strain (clade 2.3.4.4b) in complex with a previously reported neutralizing antibody. Surprisingly, we found that the receptor-binding site of this H5N1 hemagglutinin was already occupied by an α2-3-linked sialic acid and that this glycan emanated from asparagine N169 of a neighboring protomer on hemagglutinin itself. This structure thus highlights recognition by influenza hemagglutinin of an “auto”-α2-3-linked sialic acid from N169, an N-linked glycan conserved in 95% of H5 strains, and adds “auto-glycan recognition,” which may play a role in viral dispersal, to the complexities surrounding H5N1 zoonosis.

Source: Structure, https://www.cell.com/structure/abstract/S0969-2126(25)00001-2?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS0969212625000012%3Fshowall%3Dtrue

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Pre-exposure #antibody #prophylaxis protects #macaques from severe #influenza

Abstract

Influenza virus pandemics and seasonal epidemics have claimed countless lives. Recurrent zoonotic spillovers of influenza viruses with pandemic potential underscore the need for effective countermeasures. In this study, we show that pre-exposure prophylaxis with broadly neutralizing antibody (bnAb) MEDI8852 is highly effective in protecting cynomolgus macaques from severe disease caused by aerosolized highly pathogenic avian influenza H5N1 virus infection. Protection was antibody dose–dependent yet independent of Fc-mediated effector functions at the dose tested. Macaques receiving MEDI8852 at 10 milligrams per kilogram or higher had negligible impairment of respiratory function after infection, whereas control animals were not protected from severe disease and fatality. Given the breadth of MEDI8852 and other bnAbs, we anticipate that protection from unforeseen pandemic influenza A viruses is achievable.

Source: Science, https://www.science.org/doi/10.1126/science.ado6481

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#Pasteurisation temperatures effectively inactivate #influenza A viruses in #milk

Abstract

In late 2023 an H5N1 lineage of high pathogenicity avian influenza virus (HPAIV) began circulating in American dairy cattle. Concerningly, high titres of virus were detected in cows’ milk, raising the concern that milk could be a route of human infection. Cows’ milk is typically pasteurised to render it safe for human consumption, but the effectiveness of pasteurisation on influenza viruses in milk was uncertain. To assess this, here we evaluate heat inactivation in milk for a panel of different influenza viruses. This includes human and avian influenza A viruses (IAVs), an influenza D virus that naturally infects cattle, and recombinant IAVs carrying contemporary avian or bovine H5N1 glycoproteins. At pasteurisation temperatures of 63 °C and 72 °C, we find that viral infectivity is rapidly lost and becomes undetectable before the times recommended for pasteurisation (30 minutes and 15 seconds, respectively). We then show that an H5N1 HPAIV in milk is effectively inactivated by a comparable treatment, even though its genetic material remains detectable. We conclude that pasteurisation conditions should effectively inactivate H5N1 HPAIV in cows’ milk, but that unpasteurised milk could carry infectious influenza viruses.

Source: Nature Communications, https://www.nature.com/articles/s41467-025-56406-8

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#WHO accelerates efforts to support response to #Sudan {hemorrhagic fever} virus disease #outbreak in #Uganda

Brazzaville/Kampala – Following the confirmation of an outbreak of Sudan virus disease – which belongs to the same family as Ebola virus disease – in Uganda today, World Health Organization (WHO) is mobilizing efforts to support the national health authorities to swiftly contain and end the outbreak. 

WHO is deploying senior public health experts and mobilizing staff from the country office to support all the key outbreak response measures. In addition, the Organization has allocated US$ 1 million from its Contingency Fund for Emergencies to help accelerate early action, and is readying medical supplies, including personal protective equipment to deliver to Uganda from its Emergency Response Hub in Nairobi. 

While there are no licensed vaccines for the Sudan virus disease, WHO is coordinating with developers to deploy candidate vaccines as an addition to the other public health measures. The vaccines will be deployed once all administrative and regulatory approvals are obtained. 

So far one confirmed case – a nurse from Mulago National Referral Hospital in the capital Kampala – has been reported. No other health workers or patients have shown symptoms of the disease.  A total of 45 contacts, including health workers and family members of the confirmed case (deceased) have been identified and are currently under close monitoring. The identification of the case in a densely populated urban requires rapid and intense response. 

“We welcome the prompt declaration of this outbreak, and as a comprehensive response is being established, we are supporting the government and partners to scale up measures to quicky identify cases, isolate and provide care, curb the spread of the virus and protect the population,” said Dr Matshidiso Moeti, WHO Regional Director for Africa. “Uganda’s robust expertise in responding to public health emergencies will be crucial in ending this outbreak effectively.”

There have been eight previous outbreaks of the Sudan virus disease, with five occurring in Uganda and three in Sudan. Uganda last reported an outbreak of Sudan virus disease in 2022. 

“Banking on the existing expertise, we are accelerating all efforts, including expertise, resources and tools to save lives and bring the outbreak to a halt swiftly,” said Dr Kasonde Mwinga, WHO Representative in Uganda. 

Sudan virus disease is a severe, often fatal illness affecting humans and other primates that is due to Orthoebolavirus sudanense (Sudan virus), a viral species belonging to the same genus of the virus causing Ebola virus disease.  Case fatality rates of Sudan virus disease have varied from 41% to 100% in past outbreaks. There are no approved treatments or vaccines for Sudan virus. Early initiation of supportive treatment has been shown to significantly reduce deaths from Sudan virus disease. 

Source: World Health Organization, Regional Office for Africa, https://www.afro.who.int/countries/uganda/news/who-accelerates-efforts-support-response-sudan-virus-disease-outbreak-uganda

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#India - #Influenza A #H5N1 viruses of high pathogenicity (Inf. with) (non-poultry including wild birds) (2017-) - Immediate notification

A tiger and three leopards in the Widlife Rescue Centre, Gorewada Zoo, Maharashtra State.

Source: WOAH, https://wahis.woah.org/#/in-review/6218

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#Perpetuation of Avian #Influenza from Molt to Fall #Migration in Wild Swan #Geese (Anser cygnoides): An Agent-Based Modeling Approach

Abstract

Wild waterfowl are considered to be the reservoir of avian influenza, but their distinct annual life cycle stages and their contribution to disease dynamics are not well understood. Studies of the highly pathogenic avian influenza (HPAI) virus have primarily focused on wintering grounds, where human and poultry densities are high year-round, compared with breeding grounds, where migratory waterfowl are more isolated. Few if any studies of avian influenza have focused on the molting stage where wild waterfowl congregate in a few selected wetlands and undergo the simultaneous molt of wing and tail feathers during a vulnerable flightless period. The molting stage may be one of the most important periods for the perpetuation of the disease in waterfowl, since during this stage, immunologically naïve young birds and adults freely intermix prior to the fall migration. Our study incorporated empirical data from virological field samplings and markings of Swan Geese (Anser cygnoides) on their breeding grounds in Mongolia in an integrated agent-based model (ABM) that included susceptible–exposed–infectious–recovered (SEIR) states. Our ABM results provided unique insights and indicated that individual movements between different molting wetlands and the transmission rate were the key predictors of HPAI perpetuation. While wetland extent was not a significant predictor of HPAI perpetuation, it had a large effect on the number of infections and associated death toll. Our results indicate that conserving undisturbed habitats for wild waterfowl during the molting stage of the breeding season could reduce the risk of HPAI transmission.

Source: Viruses, https://www.mdpi.com/1999-4915/17/2/196

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#NASA Shares #Observations of Recently-Identified Near Earth #Asteroid {2024 YR4}

NASA analysis of a near-Earth asteroid, designated 2024 YR4, indicates it has a more than 1% chance of impacting Earth on Dec. 22, 2032 – which also means there is about a 99% chance this asteroid will not impact. Such initial analysis will change over time as more observations are gathered.  

Currently, no other known large asteroids have an impact probability above 1%. 

Asteroid 2024 YR4 was first reported on Dec. 27, 2024, to the Minor Planet Center– the international clearing house for small-body positional measurements – by the NASA-funded Asteroid Terrestrial-impact Last Alert System station in Chile. 

The asteroid, which is estimated to be about 130 to 300 feet wide, caught astronomers’ attention when it rose on the NASA automated Sentry risk list on Dec. 31, 2024. 

The Sentry list includes any known near-Earth asteroids that have a non-zero probability of impacting Earth in the future.  

An object that reaches this level is not uncommon; there have been several objects in the past that have reached this same rating and eventually dropped off as more data have come in. 

New observations may result in reassignment of this asteroid to 0 as more data come in. 

More information about asteroids, near-Earth objects, and planetary defense at NASA can be found at: https://nasa.gov/planetarydefense

Source: NASA, https://blogs.nasa.gov/planetarydefense/2025/01/29/nasa-shares-observations-of-recently-identified-near-earth-asteroid/

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The #hospital and #mortality #burden of #COVID19 compared with #influenza in #Denmark: a national observational cohort study, 2022–24

Summary

Background

The COVID-19 pandemic has been on a downward trend since May, 2022, but it continues to cause substantial numbers of hospital admissions and deaths. We describe this burden in the 2 years since May, 2022, and compare it with the burden of influenza in Denmark.

Methods

This observational cohort study included residents in Denmark from May 16, 2022, to June 7, 2024. Data were obtained from national registries, including admissions with COVID-19 or influenza (ie, having a positive PCR test for either virus from 14 days before and up to 2 days after the hospital admission date), deaths, sex, age, COVID-19 and influenza vaccination status, comorbidities, and residence in long-term care facilities. Negative binomial regression was used to estimate adjusted incidence rate ratios (aIRRs) to compare rates of hospital admissions between COVID-19 and influenza. To compare the severity of COVID-19 versus influenza among patients admitted to hospital, we used the Kaplan–Meier estimator to produce weighted cumulative incidence curves and adjusted risk ratios (aRRs) of mortality at 30 days between COVID-19 and influenza admissions.

Findings

Among 5 899 170 individuals, COVID-19 admissions (n=24 400) were more frequent than influenza admissions (n=8385; aIRR 2·04 [95% CI 1·38–3·02]), particularly during the first year (May, 2022, to May, 2023) versus the second year (May, 2023, to June, 2024; p=0·0096), in the summer versus the winter (p<0·0001), and among people aged 65 years or older versus younger than 65 years (p<0·0001). The number of deaths was also higher for patients with COVID-19 (n=2361) than patients with influenza (n=489, aIRR 3·19 [95% CI 2·24–4·53]). Among patients admitted in the winter (n=19 286), the risk of mortality from COVID-19 was higher than for influenza (aRR 1·23 [95% CI 1·08–1·37]), particularly among those without COVID-19 and influenza vaccination (1·36 [1·05–1·67]), with comorbidities (1·27 [1·11–1·43]), and who were male (1·36 [1·14–1·59]).

Interpretation

COVID-19 represented a greater disease burden than influenza, with more hospital admissions and deaths, and more severe disease (primarily among non-vaccinated people, those with comorbidities, and male patients). These results highlight the continued need for attention and public health efforts to mitigate the impact of SARS-CoV-2.

Funding

Danish Government.

Source: The Lancet Infectious Diseases, https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(24)00806-5/fulltext?rss=yes

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#Zika virus disease - #India

Situation at a glance

Between 1 January and 31 December 2024, a cumulative total of 151 Zika virus disease (ZVD) cases were reported from three states in India (Gujarat, Karnataka, and Maharashtra states). Maharashtra State reported a cumulative total of 140 ZVD cases through the Integrated Disease Surveillance Programme (IDSP). Additionally, Karnataka and Gujarat states reported ten and one cases, respectively, in 2024. As of 31 December 2024, no cases of microcephaly and/or Guillain-Barre syndrome (GBS) associated with this outbreak have been reported. Zika virus (ZIKV) is transmitted to humans by the bite of an infected Aedes mosquito. Zika virus is also transmitted from mother to fetus during pregnancy, as well as through sexual contact, transfusion of blood and blood products, and possibly through organ transplantation. There is no specific treatment available for Zika virus infection or disease.

Description of the situation

Between 1 January and 31 December 2024, a cumulative total of 151 ZVD cases were reported from three states in India (Gujarat, Karnataka, and Maharashtra states). Maharashtra State reported a cumulative total of 140 ZVD cases through the Integrated Disease Surveillance Programme (IDSP). Among the 140 cases, the majority (125 cases) were reported from Pune district, 11 from Ahmednagar district, and one case from each of Kolhapur, Sangli and Solapur districts and Mumbai suburban area. Additionally, Karnataka state reported ten cases in 2024, with seven reported from Bengaluru urban district and three from Shivamogga district. Gujarat state reported one Zika case in Gandhinagar Corporation in 2024.

The number of ZVD cases reported in 2024 in Maharashtra state is the highest since 2021 compared with respectively one, three and 18 ZIKV disease cases reported in 2021, 2022 and 2023. The number of cases reported in Karnataka state in 2024 is also the highest number reported since the first case reported in 2022.

The State IDSP Unit does not routinely disaggregate the number of ZVD cases (e.g. pregnancy status), therefore the number of ZIKV infection among pregnant women is unknown.

As of 31 December 2024, no cases of microcephaly and/or Guillain-Barre syndrome (GBS) associated with this outbreak have been reported.

Epidemiology

Zika virus is a mosquito-borne virus first identified in Uganda in 1947 in a Rhesus macaque monkey and  evidence of infection and disease in humans was reported in other African countries in the 1950s. Zika virus is transmitted to humans by the bite of an infected Aedes mosquito. Zika virus is also transmitted from mother to fetus during pregnancy, as well as through sexual contact, transfusion of blood and blood products, and possibly through organ transplantation.

Zika virus (ZIKV) can cause large epidemics, particularly when introduced in immunologically naive populations, resulting in a substantial demand on the public health system including surveillance, case management, and differential laboratory diagnostic testing especially in case of co-circulation of other mosquito-borne diseases like dengue and chikungunya.  In most cases, infection with ZIKV is asymptomatic or mildly symptomatic and of short duration. However, infection during pregnancy is associated with a risk of microcephaly and other congenital malformation in infants (congenital Zika syndrome (CZS)) as well as preterm birth and miscarriage. Some ZIKV-infected adults and children may develop neurological complications including GBS, neuropathy and myelitis.  

There is no specific treatment available for Zika virus infection or disease.

Public health response

On 3 July 2024, the Government of India issued an advisory for all States following the detection of ZIKV disease cases in Maharashtra state and the following public health measures:

-- The IDSP at the National Centre for Disease Control is mandated with surveillance and response to 40 plus outbreak-prone communicable diseases, including the ZIKV. Every State has designated laboratories, such as District Public Health Laboratories and State Referral Laboratories, under the IDSP for investigation and surveillance of these diseases.

-- Technical Guidelines for Integrated Vector Management, and effective community participation disseminated to the States for implementation.

-- Under the National Health Mission, budgetary support is provided to States/Union Territories for preventive activities such as provision of domestic breeding checkers (workers who inspect homes for mosquito breeding sites and eliminate them), involvement of accredited Social Health activists, insecticide, fogging machines, training support, awareness activities.

-- In Maharashtra, the State authority conducted active surveillance following the detection of the initial ZIKV disease cases, particularly targeting pregnant women. Close monitoring of ZIKV- positive pregnant women has been conducted. Vector control measures have been intensified in affected areas.

WHO risk assessment

Zika virus can cause large epidemics, particularly when introduced in immunologically naive populations, with a substantial demand on the public health system, including surveillance, case management, and differential laboratory diagnostic testing to differentiate ZVD from illness due to co-circulating mosquito-borne viruses like dengue and chikungunya. ZIKV is primarily transmitted by Aedes species mosquitoes, it can also be transmitted from mother to fetus during pregnancy, through sexual contact, transfusion of blood and blood products, and organ transplantation. Although 60-80% of Zika virus infections are asymptomatic or only have mild symptoms, ZIKV infection can cause GBS and microcephaly and congenital Zika syndrome (CZS) during pregnancy.

India reported its first Zika case from Gujarat State in 2016. Since then, many other States namely Tamil Nadu, Madhya Pradesh, Rajasthan, Kerala, Maharashtra, Uttar Pradesh, Delhi, and Karnataka have reported cases subsequently, but no ZIKV-associated microcephaly has been reported. Although Zika virus is not unexpected in Maharashtra state, given the wide distribution of the vectors, Aedes aegypti, and Aedes albopictus, across India, the number of ZVD cases reported in Maharashtra state in 2024 is much higher than the numbers reported in previous years and is thus unusual. The actual incidence of ZVD could be higher due to the asymptomatic or mild clinical presentation in most of the ZIKV infections, combined with varied level of awareness among clinicians. Aedes mosquito density in India varies by season and location, with the highest densities occurring during the monsoon and post-monsoon seasons. 

WHO advice

Protection against mosquito bites during the day and early evening is a key measure to prevent ZIKV infection. Special attention should be given to preventing mosquito bites among pregnant women, women of reproductive age, and young children.

Aedes mosquitoes breed in small water collections inside and around homes, schools, and workplaces. It is important to eliminate these mosquito breeding sites by appropriate methods, including covering water storage containers, removing standing water in water-holding containers such as vases and flowerpots, and cleaning up trash, unused containers, and used tyres. Community initiatives are essential to support local health authorities and national public health programmes to reduce mosquito breeding sites. Health authorities may also advise the use of larvicides and insecticides to reduce mosquito populations and disease spread. Semi-urban areas should prevent the breeding of Aedes spp., in rubber plantations and other stagnant pools of water.

Basic precautions for protection from mosquito bites should be taken by people travelling to high-risk areas, especially pregnant women. These include wearing light-colored, long-sleeved shirts and pants, ensuring rooms are fitted with screens to prevent mosquitoes from entering, and using of insect repellents that contains N,N-Diethyl-meta-toluamide (DEET), IR3535 or Icaridin according to the product label instructions.

For regions with active transmission of ZIKV, all persons with suspected ZIKV infection and their sexual partners (particularly pregnant women) should receive information about the risks of sexual transmission of ZIKV.

WHO recommends that sexually active men and women be correctly counselled about ZIKV infection and offered a full range of contraceptive methods to be able to make an informed choice about whether and when to become pregnant to prevent CZS and other possible adverse pregnancy and foetal outcomes. Men and women should be informed about the possible risk of sexual transmission of Zika virus during the three months and two months, respectively, after known or presumptive infection, and should be informed about the correct and consistent use of condoms or abstinence during that time period to prevent Zika virus infection through sexual transmission.

Women who have had unprotected sex and do not wish to become pregnant due to concerns about ZIKV infection should have ready access to emergency contraceptive services and counselling. Pregnant women should practice safer sex (including correct and consistent use of condoms) or abstain from sexual activity for the entire duration of pregnancy. Pregnant women should be encouraged to attend scheduled appointments and enhanced antenatal care and follow-up, including ultrasound imaging to detect microcephaly and other developmental anomalies associated with ZIKV infection in pregnancy, in accordance with the state/national response plan.

For regions with no active transmission of ZIKV, WHO recommends practicing safer sex, including postponing sexual debut, nonpenetrative sex, correct and consistent use of male or female condoms, and reducing the number of sexual partners, or abstinence for a period of three months for men and two months for women who are returning from areas of active ZIKV transmission to prevent infection of their sex partners. Sexual partners of pregnant women, living in or returning from areas where local transmission of ZIKV occurs, should practice safer sex or abstain from sexual activity throughout pregnancy.

WHO does not recommend any travel or trade restriction to India based on the current information available.

Further information

-- India Union Health Ministry. 3 July 2024. Union Health Ministry Issues Advisory to States in view of Zika virus cases from Maharashtra(link is external)

-- India Ministry of Health and Family Welfare. 30 July 2024. Update On Efforts Taken to Control Zika Virus in The Country(link is external)

-- WHO 2018: Zika virus disease

-- WHO guidelines for the prevention of sexual transmission of Zika virus

-- WHO Zika virus factsheet

-- Vector control operations framework for Zika virus (who.int)

-- PAHO/WHO Tool for the diagnosis and care of patients with suspected arboviral diseases (link is external)

-- Disease Outbreak News: India – Zika 2017

-- Disease Outbreak News: India – Zika 2021

Citable reference: World Health Organization (29 January 2025). Disease Outbreak News; Zika virus disease in India. Available at: https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON549

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Source: World Health Organization, https://www.who.int/emergencies/disease-outbreak-news/item/2025-DON549

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Dispersal of #influenza virus #populations within the respiratory tract shapes their evolutionary #potential

Abstract

Viral infections are characterized by dispersal from an initial site to secondary locations within the host. How the resultant spatial heterogeneity shapes within-host genetic diversity and viral evolutionary pathways is poorly understood. Here, we show that virus dispersal within and between the nasal cavity and trachea maintains diversity and is therefore conducive to adaptive evolution, whereas dispersal to the lungs gives rise to population heterogeneity. We infected ferrets either intranasally or by aerosol with a barcoded influenza A/California/07/2009 (H1N1) virus. At 1, 2, or 4 days postinfection, dispersal was assessed by collecting 52 samples from throughout the respiratory tract of each animal. Irrespective of inoculation route, barcode compositions across the nasal turbinates and trachea were similar and highly diverse, revealing little constraint on the establishment of infection in the nasal cavity and descent through the trachea. Conversely, infection of the lungs produced genetically distinct viral populations. Lung populations were pauci-clonal, suggesting that each seeded location received relatively few viral genotypes. While aerosol inoculation gave distinct populations at every lung site sampled, within-host dispersal after intranasal inoculation produced larger patches, indicative of local expansion following seeding of the lungs. Throughout the respiratory tract, barcode diversity declined over time, but new diversity was generated through mutation. De novo variants were often unique to a given location, indicating that localized replication following dispersal resulted in population divergence. In summary, dispersal within the respiratory tract operates differently between regions and contributes to the potential for viral evolution to proceed independently in multiple within-host subpopulations.

Source: Proceedings of the National Academy of Sciences of the USA, https://www.pnas.org/doi/abs/10.1073/pnas.2419985122?af=R

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