Crean vacuna recombinante contra influenza aviar H5N1

2011-05-09 Una alianza entre la UNAM y la empresa farmacéutica Boehringer Ingelheim se concretó para el desarrollo de una vacuna recombinante contra la influenza aviar subtipo H5N1, de alta patogenicidad, que inmuniza a las aves contra esa enfermedad. Con esta inoculación, que podría estar en el mercado el próximo año, obtuvieron el Premio Canifarma Veterinaria 2010, en la categoría de Desarrollo Tecnológico que, desde 1987, otorga la Cámara Nacional de la Industria Farmacéutica. Para hacer la vacuna, los investigadores desarrollaron en laboratorio una proteína recombinante producida por células de insecto, a través de un gen recombinante que se tomó del virus original. Es el vector y da el gen a una célula de insecto, la que produce la proteína recombinante, que constituye la vacuna contra la influenza aviar, resumió Laura Alicia Palomares Aguilera, del Instituto de Biotecnología de la UNAM. RECOMBINANTE. La influenza es una afección con un considerable impacto para la salud de diversas especies animales. Su control a nivel veterinario es importante para evitar pérdidas económicas y controlar el padecimiento en humanos, pues las cepas con mayor patogenicidad en el hombre son las que llegan de un hospedero animal. Tradicionalmente, las vacunas utilizadas para su control se preparan en embriones de pollo; el inconveniente es la baja disponibilidad de huevos, la posible transmisión de enfermedades, la ineficiente inactivación del virus, el manejo de este último potencialmente patógeno y la imposibilidad de diferenciar animales inmunizados de los que no lo están. Una alternativa son las recombinantes, en las que se expresa únicamente una o varias proteínas de la influenza. Las obtenidas por este medio son altamente eficientes y no generan reacciones adversas en los vacunados. El desarrollo tecnológico entre la UNAM y Boehringer Ingelheim Vetmedica, incluye la generación y mantenimiento de bancos celulares y baculovirales, la producción en biorrector con condiciones controladas, la formulación de la vacuna y las pruebas con animales. Este modelo nos permite tener una respuesta muy rápida. Si hoy tuviéramos una contingencia como la de hace unos años con la influenza, podríamos responder rápidamente con una vacuna, destacó Palomares.

Does Bird Flu + Swine Flu = Superflu?

ENLARGE IMAGE

Bad mix. Human (background, right) and bird (background, left) flu viruses combine to make worse symptoms.

Credit: thinkstock.com/cdcWhat do you get if you cross bird flu with the 2009 pandemic human virus, widely known as swine flu? Unfortunately, the answer isn't funny. A new study predicts that swapping genes between the avian and human influenza viruses may result in an even more dangerous flu.

The human influenza virus H1N1 that caused the 2009 flu pandemic, and H9N2, an avian influenza virus that is endemic in bird populations in Asia, are close cousins—close enough that they can swap genes if they find themselves in the same cell, resulting in new viruses that are a patchwork of the parent strains. Scientists suspect that some gene combinations may result in a particularly potent form of flu and ignite a pandemic in humans. But because these viruses are more likely to meet in the lungs of an Asian chicken farmer than under the nose of a virologist, researchers find it difficult to predict which gene combinations might be the most virulent and contagious.

So instead of waiting and seeing, researchers have played matchmaker and thrust the two viruses together in a test tube. A team in China generated 127 hybrid viruses and injected each one into lab mice. More than half of the hybrids were as good as their parent strains at infecting the mice, and eight of them proved to be more pathogenic, the team led by Jinhua Liu of the China Agricultural University in Beijing reports online today in theProceedings of the National Academy of Sciences.

"These are important experiments", says virologist Peter Palese of Mount Sinai Medical Center in New York City, who was not involved in the work. The viral hybrids that the Chinese team has identified are the ones that scientists might want to watch out for worldwide, he says. If these strains were recognized early, governments could launch a speedier response.

Creating highly virulent viruses in the lab is controversial, says virologist Ab Osterhaus of the Erasmus University Medical Center in Rotterdam, the Netherlands. "[But] I don't think we should shy away from these experiments. ... The more information we have, the better," he says.

He explains, however, that the hybrids that are the most virulent in mice will not necessarily be the most dangerous in humans, nor the most contagious. "Mice mirror, to a certain extent, what happens in humans," he says, but they are not perfect model animals. Liu agrees. He plans to investigate how contagious his new viral blends are in guinea pigs and ferrets—animals whose respiratory system better reflects our own feverish battle with flu.

http://news.sciencemag.org/sciencenow/2011/02/does-bird-flu-swine-flu-superflu.html?ref=hp

Diagnóstico de virus de Influenza en mamíferos y aves

PANAFTOSA-OPS/OMS Serie de Manuales Técnicos, 16 2010

El presente documento reúne todos los protocolos de las técnicas de laboratorio tanto serológicas, virológicas, y moleculares, como también los estudios de patogenicidad disponibles para el diagnóstico de la Influenza , abarcando las cepas aviares y suinas incluyendo la pandémica H1N1 2009.
Text in Spanish
http://bvs1.panaftosa.org.br/local/File/textoc/SerManTec16.pdf

Canadá detecta vírus de gripe aviária em fazenda de perus

26/11/10 - 00:00 

As autoridades canadenses confirmaram nesta quinta-feira um caso de gripe aviária em uma fazenda de perus e assinalaram que a cepa detectada é, "provavelmente, um vírus com baixo nível patogênico". A Agência de Inspeção Alimentar do Canadá (CFIA, na sigla em inglês) confirmou a presença do vírus em uma granja comercial no município de Rockwood, na província de Manitoba, e disse que está realizando testes para informar o subtipo do vírus. 

"A avaliação clínica e as análises de laboratório sugerem, por enquanto, que, provavelmente, se trata de um vírus com baixo nível patogênico", disse a CFIA através de um comunicado. A cepa H5N1 é a mais violenta e mortal deste tipo de vírus. 

Segundo a Organização Mundial da Saúde (OMS), o H5N1 provocou a morte de 260 pessoas no mundo todo (em sua maioria na Ásia) e causou o sacrifício de milhões de aves para evitar sua propagação. A CFIA disse que todas as aves infectadas (cerca de 8,2 mil) serão sacrificadas e as instalações da granja "desinfectadas".

O jornal Winnipeg Free Press assinalou que as autoridades sanitárias não detectaram nenhuma pessoa contaminada pelo vírus. Em 2004, o Canadá sofreu seu primeiro surto de gripe aviária em uma criação agrícola da província de Colúmbia Britânica, que se estendeu rapidamente e obrigou o sacrifício de, aproximadamente, 20 milhões de aves. 

Agência EFE 

http://www.agrolink.com.br/noticias/canada-detecta-virus-de-gripe-aviaria-em-fazenda-de-perus_121929.html

Levantamento da gripe aviária no Pantanal aumenta

Equipes do SFA/MS (Serviço de Saúde Animal da Superintendência Federal da Agricultura-MS) e da Iagro (Agência Estadual de Defesa Sanitária Animal e Vegetal) realizaram levantamento de amostras para monitoramento da circulação do vírus da gripe do frango na região de Corumbá. A pesquisa aumentou o número de amostras em 26%. 25/11/10 - 00:00 

Comparado com o trabalho realizado em 2009, o número de amostras no levantamento deste ano chegou a 576 na região da Curva do Leque, município de Corumbá. 

Este é o quarto ano em que o levantamento é realizado, tendo sempre resultados negativos para as amostras realizadas a partir da coleta de sangue e suabes de traquéia e cloaca das aves domésticas criadas nas fazendas pantaneiras (galinhas e patos). 

A análise das amostras é feito em laboratório oficial do Mapa (Ministério da Agricultura, Pecuária e Abastecimento) em Campinas (SP). 

A coleta foi concluída no dia 10 de novembro e deve ter os resultados divulgados nos próximos dias. 

João Ormay, fiscal agropecuário da SFA/MS, explica que existem espécies de aves migratórias oriundas de países da América do Norte que passam uma temporada no Pantanal em busca de alimento e posteriormente seguem para a região da Patagônia na Argentina. 

"Essas aves podem estar contaminadas com o vírus da Influenza Aviária e no momento que compartilham do mesmo ambiente em busca de alimento pode ocorrer risco de contágio para as aves domésticas", disse Ormay. 

Com informações do SFA/MS

http://www.agrolink.com.br/noticias/levantamento-da-gripe-aviaria-no-pantanal-aumenta_121839.html

Nuevo virus de influenza A (EUA)

November 12, 2010

Reports of Human Infections with Swine Origin Influenza A (H3N2)

The November 12, 2010 FluView reports two human infections with swine origin influenza A (H3N2) viruses in the United States. Test samples from two patients submitted by Wisconsin and Pennsylvania have been confirmed at CDC as positive for swine origin triple-reassortant (tr) H3N2 influenza viruses—viruses that normally infect pigs. While human infection with swine influenza viruses is rare, it can occur. This is most likely to occur when people are in close proximity to infected pigs, such as in pig barns and livestock exhibits housing pigs at fairs. Both of the patients with confirmed trH3N2 infection reported in FluView were in the vicinity of live pigs. Dates of illness onset in the two patients are more than six weeks apart and the viruses from the two patients have some genetic differences, confirming that these two cases are not linked. Ongoing investigations in both states have not shown any evidence of community transmission of these viruses. The most likely scenario at this point is that these are two isolated cases of human infection with swine influenza viruses that, while very rare, do occur from time to time. Both patients have fully recovered from their illnesses; however, these two cases do underscore the importance of human and animal surveillance for influenza.

These two cases reported in FluView bring the total number of human infections with swine origin influenza viruses reported to CDC since 2005 to 18. Previously, three of these reports had been swine origin A (H3N2) viruses. The Pennsylvania and Wisconsin cases bring the number of reports swine origin A (H3N2) infections in humans in the United States to five. The viruses identified in Pennsylvania and Wisconsin are similar to viruses that infected a patient in Iowa in September 2009, a patient in Kansas in August 2009 and a patient in Minnesota in May 2010.

Swine Influenza (swine flu) is a respiratory disease of pigs caused by type A influenza viruses that regularly causes outbreaks of influenza in pigs. Swine flu viruses cause high levels of illness and low death rates in pigs. Swine influenza viruses may circulate among swine throughout the year, but most outbreaks occur during the late fall and winter months similar to outbreaks in humans. There are four main influenza type A virus subtypes that have been isolated in pigs: H1N1, H1N2, H3N2, and H3N1. Most flu viruses circulating in pigs are referred to as "triple-reassortant" viruses because these flu viruses contain genes from human, swine and avian influenza viruses.

Most commonly, cases of human infection with swine-origin influenza viruses occur in people with direct exposure to pigs. The patient in Pennsylvania lives in an area where live pigs are farmed and the patient in Wisconsin became sick two days after attending a state fair where pigs were exhibited. It's important to note that swine influenza viruses are not transmitted to humans by food. You can not get swine influenza from eating pork or pork products. Eating properly handled and cooked pork and pork products is safe.

In the past, CDC received reports of approximately one human infection with a swine influenza virus every one to two years, but in the past few years, about three cases have been reported per year. Increased reporting of human infections with swine influenza could be the result of increased influenza testing capacity and capabilities in public health laboratories.

These trH3N2 viruses are different from the 2009 H1N1 virus that has been circulating in the United States since late April 2009. They are also different from human seasonal influenza A (H3N2) viruses that typically circulate among people during the flu season. Swine trH3N2 viruses commonly circulate in pigs in North America, but rarely infect humans. These viruses are different from the swine classical H1N1 or swine trH1N1 influenza viruses that also circulate in pigs in North America because they have H3N2 surface antigens. Tr H3N2 viruses first emerged in North American swine herds in the late 1990s. The H3 and N2 genes which first emerged in swine flu viruses originated from human seasonal H3N2 influenza viruses that circulated globally among humans in the late 1990s.

Although the vast majority of instances of human infection with animal influenza viruses do not result in human to human transmission, each case should be fully investigated to be sure that such viruses are not spreading among humans and to limit further exposure of humans to infected animals if infected animals are identified. Surveillance for both seasonal and novel influenza viruses is conducted by the CDC and its state and local health partners year round.

For more information about swine influenza, visithttp://www.cdc.gov/flu/swineflu/

Weekly U.S. surveillance updates are published in FluView and posted at http://www.cdc.gov/flu/weekly/fluactivitysurv.htm

Doenças em regiões de fronteira

A América Latina é a maior produtora mundial de carne de gado, aves e ovos. Mas toda essa produção pode estar ameaçada pelas enfermidades transfronteiriças.

Transgenia pode propiciar ave resistente à Influenza Aviária

14/04/2010 - 10:58 

Campinas, Abril de 2010 - Liderada pela Professora de Biologia Katherine Magor, uma equipe de pesquisadores da Universidade de Alberta, no Canadá, identificou a existência, nos patos, de um “sensor genético” que possibilita à ave hospedar naturalmente o vírus da Influenza Aviária sem ser por ele influenciado ou sem ficar doente.

O mecanismo localizado, identificado pela sigla RIG-I (retinoic acid-inducible gen – I) permite que o sistema imunitário do pato hospede o vírus sem qualquer efeito adverso, mas não impede que ele infecte com facilidade os galináceos, de onde se dissemina rapidamente e alcança até mesmo o homem.

As galinhas não possuem o gene RIG-I e, por isso, morrem num espaço de tempo de até 18 horas depois de serem infectadas. Nos experimentos realizados, os pesquisadores de Alberta transferiram o RIG-I do pato para células de galinhas que, dessa forma, tiveram aumentadas suas defesas contra o vírus da Influenza Aviária a ponto de a replicação do vírus ter sido reduzida à metade.

Pode não ser, ainda, a solução para o problema. Mas a equipe da Professora Magor entende que a descoberta pode revolucionar a indústria avícola, equacionando a questão da Influenza Aviária. E o caminho é adotar a transgenia para desenvolver galináceos (frangos, poedeiras, reprodutores) resistentes ao vírus.

Clique aqui para acessar um resumo dos resultados obtidos pelos pesquisadores de Alberta. Eles foram publicados na edição de 23 de março de 2010 dos Proceedings from the National Academy of Sciences.

Influenza Virus Transmission from Horses to Dogs, Australia

Peter D. Kirkland,  Deborah S. Finlaison, Ellie Crispe, and Aeron C. Hurt

Author affiliations: Elizabeth Macarthur Agricultural Institute, Menangle, New South Wales, Australia (P.D. Kirkland, D.S. Finlaison); Warwick Farm Equine Centre, Warwick Farm, New South Wales, Australia (E. Crispe); and World Health Organization Collaborating Centre for Reference and Research on Influenza, North Melbourne, Victoria, Australia (A.C. Hurt)

Suggested citation for this article

Abstract
During the 2007 equine influenza outbreak in Australia, respiratory disease in dogs in close contact with infected horses was noted; influenza (H3N8) virus infection was confirmed. Nucleotide sequence of the virus from dogs was identical to that from horses. No evidence of dog-to-dog transmission or virus persistence in dogs was found.

Respiratory disease in dogs caused by type A influenza virus was first noted in racing greyhounds in Florida in January 2004 (1). This subtype H3N8 virus has a presumptive but unidentified equine origin. The geographic extent of infection in racing greyhounds and in pet dogs suggest that this virus has become enzootic to the United States (1,2).

In the United Kingdom, pneumonia in dogs and influenza (H3N8) virus have been retrospectively linked, and subtype H3N8 infections have been identified serologically in dogs likely to have been in close contact with horses during the 2003 outbreak of equine influenza (3,4). A 78-bp segment of the hemagglutinin (HA) gene identified in dogs with pneumonia had complete homology with local equine strains (3). Unlike the situation in the United States, no evidence of continuing circulation of an influenza virus of equine origin in the canine population has been found in the United Kingdom.

In Australia, in late 2007, an outbreak of equine influenza virus (EIV) infection occurred in horses. During this outbreak, respiratory disease was noted in dogs of various ages and breeds that were kept near infected horses. Investigations were undertaken to exclude influenza virus infection.

The Study

The first reported case was in a dog near a large stable; the dog became inappetant and lethargic and had had a slight nasal discharge and a persistent cough for several days. Over the next 2–3 weeks, dogs in or near stables with infected horses, including dogs whose owners were handling infected horses or dogs (n = 6) that were only housed with infected dogs, were examined. Samples were also collected from dogs kept with horses at 5 other locations 20–60 km from the first case. Of the 40 dogs, examined, 10 had clinical signs consistent with influenza (anorexia, lethargy, and, for some, a harsh cough that persisted for several weeks). All affected dogs recovered.

Nasal swabs and serum were collected from each of the 40 dogs; 23 were seropositive according to influenza type A blocking ELISA (5) and hemagglutinin inhibition (HI) assay (5) using A/equine/Sydney/2007 virus as antigen (Table). HI titers were 16–256 (geometric mean 122). Results were discordant for 5 dogs: for 2, HI titer was high but ELISA results were negative; for 3, ELISA results were positive but HI titer was negative. These discrepancies may have been resolved had later sampling been possible. Convalescent-phase serum samples were collected 14–16 days later from 26 of the dogs; seroconversion was noted for 4 of the 5 dogs with discordant ELISA and HI results. Testing of 19 dogs 2 years later showed no change in HI titer, although ELISA results were negative for each. Each seropositive dog had been in close proximity to EIV-infected horses but not always in direct contact. No evidence of lateral transmission was found for dogs that did not have contact with horses.

Nasal swabs from 1 clinically healthy dog had a positive result in an influenza A real-time reverse transcription–PCR assay (5) on 2 consecutive days. The dog remained clinically healthy and was seropositive (titer 64) on day 16 after the first positive swab was collected. Attempts to isolate virus from these swabs were unsuccessful.

Nucleic acid sequencing was conducted for the HA, neuraminidase (NA), and matrix (M) genes amplified by PCR from the RNA purified from 2 samples from this dog (A/canine/Sydney/6525/2007 and A/canine/Sydney/6692/2007) and from a nasal swab from an infected horse (A/equine/Sydney/6085/2007) in the same stable (GenBank accession nos. GU045761–GU045769). Sequences were aligned with representative sequences from GenBank by using Clustal W (www.clustal.org) before phylogenetic trees with bootstrapping were generated (n = 1,000; random seed n = 111) with MegAlign (Lasergene; DNAStar, Madison, WI, USA). Complete nucleotide homology was found for each of the HA, NA, and M gene sequences from the 2 dogs and the sequence from the infected horse in the same stable (A/equine/Sydney/6085/2007).

Figure

Figure. Phylogenetic trees of influenza subtype H3N8 viruses showing analyses conducted on A) hemagglutinin genes, B) neuraminidase genes, and C) matrix genes...

When influenza subtype H3N8 sequences from horses and dogs were compared with other subtype H3N8 sequences in GenBank, the HA, NA, and M sequences were most similar to strains A/equine/Kanazawa/1/2007 and A/equine/Ibaraki/1/2007, which were isolated during the 2007 equine influenza outbreak in Japan (Figure). The HA, NA, and M gene sequences from the dogs in Australia were positioned on separate clades of the phylogenetic trees, as opposed to those from subtype H3N8 viruses from dogs in the United States, which all grouped closely together (Figure).

Conclusions

Researchers in Japan have described transmission of EIV from 3 experimentally infected horses to 3 dogs individually housed with each horse (6). Their findings were mostly consistent with ours, but there were some differences. Both studies showed direct linkage between active influenza virus infection in dogs and horses. Because some naturally infected dogs were only in the vicinity of stables and not in direct contact with horses, we believe that EIV may be readily transmitted from horses to dogs in close proximity. The mechanism of spread remains unclear, although in the United Kingdom aerosol transmission was believed to be a major means of spread to dogs (4). Studies conducted during the equine influenza outbreak in Australia indicate that the levels of virus excretion from horses not previously exposed to the virus can be extremely high (A.J. Read et al., unpub. data). Although humans readily spread virus from horse to horse, either directly during handling or by fomite transmission, human transmission of EIV to dogs that were not in the immediate vicinity of infected horses was not found. Similarly, dog-to-dog transmission was not found when infected dogs were transported and kept with other dogs in urban locations where there was no opportunity for contact with horses.

Although clinical signs were not observed for any of the dogs in Japan, >35% of the naturally infected dogs in Australia exhibited clinical signs, some quite severe and protracted. Nevertheless, virus was rarely detected in nasal secretions of the dogs in Australia, and there was no evidence of horizontal transmission to other dogs. The lack of clinical signs in experimentally infected dogs may be because of the small numbers of dogs or because of inoculum attenuation after passage in embryonated chicken eggs. That the experimentally infected dogs in Japan also had lower HI titers than did naturally infected dogs may be relevant.

Finally, when 19 of the dogs in Australia were tested 2 years after infection and without opportunity for reexposure, with only 1 exception, the HI antibody titers had not changed. This finding supports the interpretation that antibodies detected in dogs in the United Kingdom (3,4) had been acquired during the equine influenza outbreak several years earlier.

The nucleotide gene sequences encoding the 2 surface proteins (HA and NA) and the M protein from the infected dog in Australia matched those from the horse with which it had contact and did not have any of the nucleotide changes that have been identified in viruses from dogs in the United States (2). Such changes may be critical to, or a consequence of, the adaptation of EIVs to dogs and may play a role in enhancing the infectivity of these viruses for dogs because there is no evidence of continuing circulation of virus in dogs in Australia.

Acknowledgments

We are indebted to the staff of the Virology Laboratory for technical support and to the NSW Department of Primary Industries for funding. The Melbourne WHO Collaborating Centre for Reference and Research in Influenza is supported by the Australian Government Department of Health and Ageing.

Dr Kirkland is a veterinary virologist and head of the virology laboratory at the Elizabeth Macarthur Agricultural Institute. His research interests include the epidemiology and pathogenesis of viral diseases of animals, development of rapid diagnostic assays, and new and emerging diseases.

References

1. Crawford PC, Dubovi EJ, Castleman WL, Stephenson I, Gibbs EP, Chen L, et al. Transmission of equine influenza virus to dogs. Science. 2005;310:482–5. PubMed DOI
2. Payungporn S, Crawford PC, Kouo TS, Chen L, Pompey J, Castleman WL, et al. Influenza A virus (H3N8) in dogs with respiratory disease, Florida. Emerg Infect Dis. 2008;14:902–8. PubMed DOI
3. Daly JM, Blunden AS, MacRae S, Miller J, Bowman SJ, Kolodziejek J, et al. Transmission of equine influenza to English foxhounds. Emerg Infect Dis. 2008;14:461–4. PubMed DOI
4. Newton R, Cooke A, Elton D, Bryant N, Rash A, Bowman S, et al. Canine influenza: cross-species transmission from horses. Vet Rec. 2007;161:142–3.
5. Selleck PW, Kirkland PD. 2009. Avian influenza. In: Australian and New Zealand standard diagnostic procedures for animal diseases, Sub-Committee on Animal Health Laboratory Standards for Animal Health Committee, Australia [cited 2010 Feb 14]. http://www.scahls.org.au
6. Yamanaka T, Nemoto M, Tsujimura K, Kondo T, Matsumura T. Interspecies transmission of equine influenza virus (H3N8) to dogs by close contact with experimentally infected horses. Vet Microbiol. 2009; 139:351–5.

Figure

Figure. Phylogenetic trees of influenza subtype H3N8 viruses showing analyses conducted on A) hemagglutinin genes, B) neuraminidase genes, and C) matrix genes...

Table

Table. Clinical signs and serologic findings for 40 dogs exposed to equine influenza virus, Australia, October 2007

Suggested Citation for this Article

Kirkland PD, Finlaison DS, Crispe E, Hurt AC. Influenza virus transmission from horses to dogs, Australia. Emerg Infect Dis [serial on the Internet]. 2010 Apr [date cited].http://www.cdc.gov/EID/content/16/4/699.htm

DOI: 10.3201/eid1604.091489