Rationale

The occurrence of cases of human disease increases the chance that the virus may adapt or reassort to become transmissible from human to human, especially if coinciding with a seasonal outbreak of influenza. Measures are needed to detect and prevent spread of disease.

Rare instances of transmission to a close contact ­ for example, in a household or healt-hcarer setting ­ may occur, but do not alter the man attribute of this phase, i.e. that the virus is essentially not transmissible from human to
human.

Definition of new: a subtype that has not circulated in humans for at least several decades and to which the great majority of the human population therefore lacks immunity.

Examples:

One or more unlinked human cases with a clear history of exposure to an animal source/non-human source (with laboratory confirmation in a WHO-designated reference laboratory).

Rare instances of spread from a case to close household or unprotected health-care contacts without evidence of sustained human-to-human transmission.

One or more small independent clusters of human cases (such as family members) who may have acquired infection from a common source or the environment, but for whom human-to-human transmission cannot be excluded.

Persons whose source of exposure cannot be determined, but are not associated with clusters

23 May 2006

The Ministry of Health in Indonesia has confirmed an additional case of human infection with the H5N1 avian influenza virus. The case occurred in a 32-year-old man. He developed symptoms on 15 May and died on 22 May.

The case is part of a family cluster in the Kubu Sembelang village, Karo District, of North Sumatra. The man is the seventh member of an extended family to become infected with the H5N1 virus and the sixth to die. An additional person, who was the first member of the family to fall ill, died of respiratory disease on 4 May. No specimens were taken prior to her burial and the cause of her death cannot be determined. However, as her clinical course was compatible with H5N1 infection, epidemiologists at the outbreak site include this woman as the initial case in the cluster.

The newly confirmed case is a brother of the initial case. Specimens were taken on 21 May and flown the same day to Jakarta. Tests run overnight confirmed his infection. His 10-year-old son died of H5N1 infection on 13 May. The father was closely involved in caring for his son, and this contact is considered a possible source of infection.

Although the investigation is continuing, preliminary findings indicate that three of the confirmed cases spent the night of 29 April in a small room together with the initial case at a time when she was symptomatic and coughing frequently. These cases include the woman’s two sons and a second brother, aged 25 years, who is the sole surviving case among infected members of this family. Other infected family members lived in adjacent homes.

All confirmed cases in the cluster can be directly linked to close and prolonged exposure to a patient during a phase of severe illness. Although human-to-human transmission cannot be ruled out, the search for a possible alternative source of exposure is continuing. (HUMAN TO HUMAN NO FURTHER SOURCE IDENTIFIED)

18 May 2006

The Ministry of Health in Indonesia has confirmed an additional seven cases of human infection with the H5N1 avian influenza virus. Six of the cases were fatal.

One fatal case, in a 38-year-old woman, occurred in the city of Surabaya, in East Java. She developed symptoms on 2 May, was hospitalized on 7 May, and died on 12 May. The case is the first reported from this area.

Avian influenza – situation in Egypt - update 5

21 April 2006

The Ministry of Health in Egypt has informed WHO of the country’s fourth death from H5N1 avian influenza. The death occurred in a previously announced patient, an 18-year-old girl from the northern governorate of Minufiyah. She developed symptoms on 5 April and died on 14 April.

Avian influenza – situation in China – update 9

19 April 2006

The Ministry of Health in China has confirmed the country’s 17th case of human infection with the H5N1 avian influenza virus. The case occurred in a 21-year-old male migrant worker employed in Wuhan City, Hubei Province. He developed symptoms on 1 April. He is presently hospitalized in critical condition.

The man’s source of exposure is under investigation. No poultry outbreaks have been reported in Hubei Province since November 2005. His close contacts have been placed under medical observation.

Avian influenza – situation in Azerbaijan - update 3

11 April 2006

Tests conducted at a WHO collaborating laboratory in the United Kingdom have retrospectively identified an additional human case of H5N1 infection. The case is a 17-year-old girl who developed symptoms on 11 March. She was seriously ill with bilateral pneumonia but has since fully recovered and been discharged from hospital. Early in her course of illness, a diagnosis of H5N1 infection was presumed based on her clinical symptoms and preliminary laboratory results, and she was treated accordingly.

Her 15-year-old cousin, previously confirmed by WHO, developed symptoms on the same day and was hospitalized in critical condition. She has also fully recovered and been discharged from hospital. Both girls, who are neighbours, reside in the small Daikyand settlement in Salyan rayon, where 7 of the 8 cases in Azerbaijan occurred. Active house-to-house surveillance in the settlement has failed to detect any further cases.

he Ministry of Health in Indonesia has confirmed an additional case of human infection with the H5N1 avian influenza virus. The case, which was fatal, occurred in a 20-month-old girl who resided in Kapuk, West Jakarta. She developed symptoms of fever and cough on 17 March, was hospitalized on 22 March, and died on 23 March.

Field investigation found a history of deaths in a chicken flock near her home about one week prior to symptom onset.