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African Mystery virus identified

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  • African Mystery virus identified

    Mystery virus identified

    12 October 2008, 15:20The mystery viral haemorrhagic fever which killed three people in South Africa has been provisionally identified as an arenavirus, the National Institute for Communicable Diseases and the Department of Health said on Sunday.

    "The causative agent of the disease...may be a rodent-born arenavirus related to the Lassa fever virus of West Africa," NICD's Dr Lucille Blumberg said at the Charlotte Maxexe Johannesburg Academic Hospital.

    She said tests done by the NICD and the Centers for Disease Control in Atlanta, US, indicated that the disease seemed to be a kind of an arenavirus. The World Health Organisation has also been providing technical assistance.

    Arenaviruses cause chronic infections in multimammatic mice - a kind of wild mouse - who excrete the virus in their urine which can then contaminate human food or house dust.

    Viruses similar to the Lassa fever virus has been found in rodents in Africa, but other than in West Africa have not been found to cause diseases in humans.

    She said there was no indication that arenaviruses which could cause disease in humans were present in South African rodents.

    Blumberg said further tests still needed to be done.

    "It needs to be determined whether it is a previously unrecognised member of the arenaviruses and what its distribution is," she said.

    The NICD's Robert Swanepoel there were viruses of this family in Southern Africa but that this could be an undiscovered kind.

    "Not every country has been thoroughly searched,"
    he said.

    He said the kind of rodents who carried the virus were not generally found in urban areas.

    "They are out there but attracted [to human dwellings] if there is inadequate waste disposal."

    Crop disposal and animal feed also sometimes attracted them, he said.

    He said the kinds of viruses could range from causing mild fevers to being lethal.

    There were only three cases to go on for the kind of arenavirus now discovered but "it looks like it is very lethal," he said.

    Head of the NICD's Special Pathogens Unit, Dr Janusz T Paweska, said the arenavirus diagnosis came about after a number of tests.

    Biopsys conducted on the last two victims where infected tissues, skin, liver and muscles were tested were critically important in being able to make a diagnosis.

    A blood sample obtained in Zambia from the first victim also confirmed test results.

    He said doctors were now waiting for the virus to grow in cell culture to conduct further tests to identify what strain it was.

    Gauteng health MEC said the first victim of the virus was 36-year-old Cecilia van Deventer, who was airlifted from Zambia to the Morningside Medi Clinic in Sandton on September 12 in a critical condition.

    She is known to have lived in a smallholding on the outskirts of Lusaka where she kept three horses, although the exact point of contamination has never been discovered.

    She fell ill on September 8 and was treated in three different hospitals in Lusaka. Once in South Africa she was treated for tick bite fever and other potential infections, but died two days later.

    She was not tested for viral haemorrhagic fever.

    On September 27 a Zambian paramedic who accompanied her into the country was admitted into the hospital with similar flu-like symptoms, fever and a skin rash and viral haemorrhagic fever was queried.

    He developed diarrhoea, severe headaches, nausea and vomiting and although he initially seemed to respond to treatment, died on October 2 at the clinic.

    A third victim of the virus was a nurse from Morningside Medi-Clinic who attended to Deventer.

    She became ill with fever 18 days after Deventer was admitted to the hospital and consulted a general practitioner, receiving intravenous therapy.

    She was then referred to Robinson Hospital in Randfontein and later transferred due to a bedding shortage to Sir Albert Clinic. Here she was treated for a suspected case of meningitis.

    Her condition deteriorated and she died last Sunday.

    A fourth person, a contract cleaner working at Morningside Medi-clinic Maria Mokubung, 37, died in Charlotte Maxeke Academic hospital.

    Earlier this week the health department said her death was not related to viral haemorrhagic fever.

    On Sunday, Blumberg said a female nurse and a male paramedic were currently in isolation after they were in contact with the deceased.

    The paramedic had contact with Deventer and after developing flu-like symptoms and a fever was admitted to Flora clinic. He was subsequently transferred to Morningside medi-clinic and diagnosed with kidney stones.

    On Sunday Blumberg said it was "less likely" he had the virus.

    The second person in isolation is a nurse who had contact with a paramedic that died. She has developed symptoms similar to the three deceased and is receiving anti-viral medication called ribavirin.

    The department of health said she was presently stable.

    Blumberg said she "highly suspect" to have contracted the virus and could not say further how her condition was likely to progress.

    This week three other people who had been hospitalised after contact with the deceased were discharged.

    On Friday morning the eleven year-old son of the nursing sister who died and his 23- year-old nanny were discharged.

    A cleaning supervisor at Morningside Medi-Clinic who had been admitted to the Chris Hani Baragwanath Hospital on Monday with symptoms of viral haemorrhagic fever was also released.

    On Sunday,Hlongwa said she was currently "well".

    All three continued to be monitored as part of the disease surveillance system currently tracking 151 people who had contact with the deceased.

    Blumberg said arenaviruses could cause a disease which spreads from human to human through contact fluid.

    In hospital settings, special precautions were needed when nursing patients.

    People in contact with those who have contracted the virus must be monitored for 21 days following their last contact with the patient.

    Their body temperature is monitored and those who develop fever or illness are admitted to an isolation ward in the hospital.

    Blumberg said there was a drug which showed promising results in treating patients if their illnes was recognised early.

    Those who have been in contact with patients but are well, do not spread infection.

    On Sunday, Gauteng health MEC Brian Hlongwa said the diagnosis of the virus was a step forward.

    "We are now a step further because we know specifically what we are dealing with."

    However, it was still vital to conduct more tests to find out kind of arenavirus it was, he said.

    Director General Thami Mseleku cautioned South Africans not to now fear that every mouse that came their way contained the virus.

    Since the virus first broke out, medical officials have been at pains to emphasise that the general public is not at risk as only people who were in direct contact with the bodily fluids of a person who had a confirmed case of the virus could be infected. - Sapa
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  • #2
    Re: African Mystery virus identified

    Mystery S.Africa disease may be rodent borne

    Sun 12 Oct 2008, 14:27 GMT

    JOHANNESBURG (Reuters) - A disease that has killed three people in South Africa and forced others into isolation wards may be rodent borne, a health official said on Sunday, SAPA news agency reported.
    All three have died from external and internal bleeding. The first was a patient from Zambia flown to South Africa for treatment. A paramedic who accompanied her, and a nurse from the Morningside clinic where she was taken, also died.
    "The causative agent of the disease ... may be a rodent borne arenavirus related to the lassa fever virus of West Africa," SAPA quoted Lucille Blumberg of the National Institute for Communicable Diseases as saying.
    Blumberg could not be reached directly and the health authorities declined to comment on the report.
    Arenaviruses can cause a type of haemorrhagic fever in rodents. Lassa fever is an acute viral haemorrhagic fever endemic to West Africa that may be spread from rodents to humans through contact with faeces and urine.
    Last week, the health authorities sent blood samples from the victims to the U.S. Centers for Disease Control and Prevention in Atlanta.
    SAPA said a nurse and a paramedic were being monitored in an isolation ward after showing symptoms of the disease.


    • #3
      About arenaviruses


      What are the Arenaviridae?
      The Arenaviridae are a family of viruses whose members are generally associated with rodent-transmitted disease in humans. Each virus usually is associated with a particular rodent host species in which it is maintained. Arenavirus infections are relatively common in humans in some areas of the world and can cause severe illnesses.

      The virus particles are spherical and have an average diameter of 110-130 nanometers. All are enveloped in a lipid (fat) membrane. Viewed in cross-section, they show grainy particles that are ribosomes acquired from their host cells. It is this characteristic that gave them their name, derived from the Latin "arena," which means "sandy." Their genome, or genetic material, is composed of RNA only, and while their replication strategy is not completely understood, we know that new viral particles, called virions, are created by budding from the surface of their hosts’ cells.

      Vero E6 tissue culture cell infected with an arenavirus. Image shows extracellular virus particles budding from the cell surface. Click the image to see a high-resolution version. Image courtesy Cynthia Goldsmith, MS, Infectious Disease Pathology Activity, DVRD, NCID, CDC. Go to high-resolution version.

      When were the members of this virus family recognized?

      The first arenavirus, lymphocytic choriomeningitis virus (LCMV), was isolated in 1933 during a study of an epidemic of St. Louis encephalitis. Although not the cause of the outbreak, LCMV was found to be a cause of aseptic (nonbacterial) meningitis. By the 1960s, several similar viruses had been discovered and they were classified into the new family Arenaviridae. Since Tacaribe virus was found in 1956, new arenaviruses have been discovered on the average of every one to three years. A number of arenaviruses cause hemorrhagic disease. Junin virus, isolated in 1958, was the first of these to be recognized. This virus causes Argentine hemorrhagic fever in a limited agricultural area of the pampas in Argentina. Several years later, in 1963, in the remote savannas of the Beni province of Bolivia, Machupo virus was isolated. The next member of the virus family to be associated with an outbreak of human illness was Lassa virus in Africa in 1969. Most recently, Guanarito and Sabia viruses were added to this family.

      What viruses are included in the virus family? (Incomplete list (ed))

      The arenaviruses are divided into two groups: the New World or Tacaribe complex and the Old World or LCM/Lassa complex. Viruses in these groups that cause illness in humans are listed below:

      Virus - Disease
      Lassa virus - Lassa fever
      Junin virus - Argentine hemorrhagic fever
      Machupo virus - Bolivian hemorrhagic fever
      Guanarito virus - Venezuelan hemorrhagic fever
      Sabia - Brazilian hemorrhagic fever

      What kinds of animal hosts do these viruses have?

      These viruses are zoonotic, meaning that, in nature, they are found in animals. Each virus is associated with either one species or a few closely related rodents, which constitute the virus’ natural reservoir. Tacaribe complex viruses are generally associated with the New World rats and mice (family Muridae, subfamily Sigmodontinae). The LCM/Lassa complex viruses are associated with the Old World rats and mice (family Muridae, subfamily Murinae). Taken together, these types of rodents are located across the greater proportion of the earth’s land mass, including Europe, Asia, Africa, and the Americas. One notable exception is Tacaribe virus, found in Trinidad, which was isolated from a bat.

      How are arenaviruses spread?

      The rodent hosts of arenaviruses are chronically infected with the viruses; however, the viruses do not appear to cause obvious illness in them. Some Old World arenaviruses appear to be passed from mother rodents to their offspring during pregnancy, and thus remain in the rodent population generation after generation. Some New World arenaviruses are transmitted among adult rodents, likely via fighting and inflicting bites. Only a portion of the rodents in each host species is infected at any one time, and in many cases only in a limited portion of the host’s geographical range. The viruses are shed into the environment in the urine or droppings of their infected hosts.
      Human infection with arenaviruses is incidental to the natural cycle of the viruses and occurs when an individual comes into contact with the excretions or materials contaminated with the excretions of an infected rodent, such as ingestion of contaminated food, or by direct contact of abraded or broken skin with rodent excrement. Infection can also occur by inhalation of tiny particles soiled with rodent urine or saliva (aerosol transmission). The types of incidental contact depend on the habits of both humans and rodents. For example, where the infected rodent species prefers a field habitat, human infection is associated with agricultural work. In areas where the rodent species’ habitat includes human homes or other buildings, infection occurs in domestic settings.

      Some arenaviruses, such as Lassa and Machupo viruses, are associated with secondary person-to-person and nosocomial (health-care setting) transmission. This occurs when a person infected by exposure to the virus from the rodent host spreads the virus to other humans. This may occur in a variety of ways. Person-to-person transmission is associated with direct contact with the blood or other excretions, containing virus particles, of infected individuals. Airborne transmission has also been reported in connection with certain viruses. Contact with objects contaminated with these materials, such as medical equipment, is also associated with transmission. In these situations, use of protective clothing and disinfection procedures (together called barrier nursing) help prevent further spread of illness.
      Separate the wheat from the chaff


      • #4
        Re: African Mystery virus identified

        <TABLE class=border id=HEADLINES cellSpacing=0 cellPadding=0 width="100%" bgColor=#b3d2f3 border=0><TBODY><TR><TD class=fptextBlack style="PADDING-RIGHT: 5px; PADDING-LEFT: 5px; PADDING-BOTTOM: 5px; PADDING-TOP: 5px" bgColor=#e6e6e6>Mystery virus identified as new strain 24/10/2008 06:27:40
        </TD></TR><TR><TD class=fptextBlack bgColor=#ffffff>

        Health officials say the killer bug that has hit Gauteng is a new strain of an Arena Virus.

        Three people have died in Johannesburg after contracting the disease in the last month and a nurse at the Morningside Medi-Clinic is in a serious condition.

        At first doctors were unable to determine what type of viral haemorrhagic fever it was but they found preliminary evidence that the virus is carried by wild rodents.

        Chief Director of Communicable Diseases at the Health Department Frew Benson says they have been able to identify it as part of the arena virus family but the virus itself is new.

        It has not been described as yet. They are obviously in the process of recording all the characteristics of the virus so that it can be given a name,” said Benson.

        Benson says there is no need for South Africans to panic as this virus has been contained.

        “The outbreak has been contained at that specific hospital at this time,” reassured Benson.