Introduction

The current influenza concern is largely centered around the novel influenza A H1N1 in humans. It is caused by a new virus, the result of a “quadruple reassortment” of the H1N1 virus from North American swine, North American avian, North American human and eurasian swine.

The novel influenza A H1N1 flu in humans is escalating globally with 50 countries infected worldwide as at today’s date (May 28th, 2009 at 6:00 am). The rapid spread of the novel influenza A H1N1 poses the biggest pandemic threat, especially considering the potential for further mutation.

Conversely H5N1outbreaks are reported less frequently except in countries where endemicity has been established, namely China and Viet Nam in south east Asia and Egypt in Africa.

The WHO influenza pandemic alert remains at level 5 as a result of the recent outbreaks and rapid spread of the novel influenza A H1N1virus. This alert is only one level short of a full-blown pandemic situation.

The data and information contained in this update has been gathered from different sources. While most information is obtained from officials sources, much of it is too new and may not be scientifically proven. It is provided for purposes of informing the general public to maintain vigilance and preparedness for rapid response, rather than for scientific consumption.

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Global distribution

At the time of reporting, May 28th, the novel H1N1 influenza has been reported in 50 countries (table 1) with a total of 15,148 confirmed cases worldwide including 99 deaths (85 in Mexico, 11 in USA, 2 in Canada and 1 in Costa Rica). 1,779 new confirmed cases were reported between Monday, 25 May at 6:00 am and today, 28 May at 6:00 am. There have been five new countries involved in the outbreak: Dominican Republic, Uruguay, Czech Republic, Bahrain and Singapore.

As the number of A (H1N1) flu cases rises and given the fact that the influenza virus is genetically unstable and has an unpredictable behavior, countries must plan for the long term.

No A (H1N1) Flu cases have so far been confirmed in Africa, and although 25 suspected cases have been reported in nine countries. Twelve of these have tested negative, while the remaining are still under laboratory investigation.

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Table 1: Worldwide distribution of Influenza A H1N1 cases by country

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Transmission

Since the beginning of the ongoing outbreak in March 2009, evidence suggests that the main route of human-to-human transmission of this new influenza A H1N1 virus is via respiratory droplets, which are expelled by speaking, sneezing or coughing. This mode of transmission has also been reported to cause human-pig transmission in Alberta, Canada.

Role of animals and animal products

Pigs are the only domestic animal linked to H1N1 so far. However, there is currently no evidence that pigs are playing a role in the current spread of the disease. There is also no indication that the disease in humans was preceded by an outbreak in pigs. Furthermore, influenza viruses are not known to be transmissible to people through eating processed pork or other food products derived from pigs. The OIE, WHO and FAO jointly maintain that imposition of ban measures related to import of pigs and pig products is unwarranted and does not comply with international standards published by relevant international standard-setting bodies for animal health and food safety. However, authorities and consumers should ensure that meat from sick or dead pigs are not processed or used for human consumption.

On the other hand, the first transmission of the influenza A H1N1 virus from humans to a herd of pigs in Alberta, Canada was notified to OIE on 5th May 2009. The virus is new and differs from the H1N1 influenza virus that is responsible for the “classical” swine influenza, which usually presents as a mild disease in pigs and rarely causes serious symptoms in humans.

Due to the potential or eventual interactions between human and porcine populations, health and agricultural authorities are strongly advised to work in close coordination in order to promote and facilitate active surveillance in people who interact directly with pigs. Furthermore, as stated by OIE and FAO recommendations, active surveillance should also include pig populations for early detection of new viruses that can compromise the human and animal health.

The OIE has recommended that while it develops appropriate standards for this emerging disease, countries that experience outbreaks of flu-like disease in pigs should keep all animals from the affected farm in strict isolation and maintain farm-to-farm quarantine until it has been rigorously demonstrated by their Veterinary Services that they are not infected with the influenza A H1N1 virus.

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Highly Pathogenic Avian Influenza (H5N1)

The last case of H5N1 in birds, according to the latest OIE update, was reported on 28th of May 2009 from Mongolia causing deaths in wild bird species.

Outbreaks of H5N1 in poultry continue to be reported from countries in Asia namely, China, Bangladesh, Vietnam, India, Laos and Nepal. In Africa, Egypt has become endemic of the disease in poultry associated with sporadic human cases.

Highly pathogenic avian influenza (H5N1) outbreaks in humans have reduced drastically since January 2009 and are being reported in only 3 countries namely, China, Egypt and Viet Nam. In Africa, cases continue to be reported from Egypt where 7 new cases were reported from 13 to 28 May 2009, all in children under 5 years of age. The seemingly high concentration of recent H5N1 infections in children below 5 years and the reduced mortality of the virus in Egypt is an interesting evolution of the disease’s epidemiology in the country.

The global cumulative incidence for 2009 is 36 cases (China 7, Egypt 25 and Viet Nam 4) with 12 deaths (China 4, Egypt 4 and Viet Nam 4).

Considering the high mortality and morbidity of H5N1 influenza and the ability of H1N1 to spread from human-human, there is danger that if re-assortment occurs between the 2 viruses, it could produce an extremely dangerous sub-type capable of high morbidity and mortality among poultry and humans. It is therefore important for veterinary and human health authorities to intensify joint monitoring of flu-like disease in their populations and take urgent control measures where infection is suspected to minimize chances of reassortment.

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Advisory

The Interafrican Bureau for Animal Resources is directly supporting preparedness efforts against avian and human influenza in 47 Africa ACP countries through the EC-supported SPINAP-AHI programme. National veterinary authorities and their public health counterparts are advised to enhance their surveillance for influenza like symptoms in swine, human and poultry populations. Any suspicions spotted should be sampled for confirmatory diagnosis. Specimen sharing and other recommended best practices developed by the OIE, WHO and FAO should be followed.

Additionally, the basic personal hygiene measures recommended by WHO and stringent bio-security around animal production units should be upheld.

The following measures are recommended to all countries:

1. Heighten the surveillance of influenza and related diseases.
2. Strengthen diagnostic capacity to ensure early detection of and response to the disease.
3. Acquire appropriate protective devices (such as masks) and PPEs in readiness for pandemic intervention.
4. Strengthen communication and sensitisation for risk reduction and behaviour change in order to limit transmission of the disease.
5. Enhance reporting of suspected and confirmed cases of the disease using the appropriate national/international channels.

Support lent to countries through the EC-funded SPINAP-AHI programme can to a large extent be used for the interventions listed above that are part of their grant contracts or their amended versions.

The AU-IBAR will, in collaboration with other technical agencies continue to closely monitor the influenza A H1N1 situation and inform member states on a continuous basis.