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Public Health Alert: Meningococcal disease

Meningococcal disease is a serious illness caused by bacterial infection that can lead to meningitis (inflammation of the lining of the brain and spinal cord) and septicaemia (blood poisoning). There are several different groups of the meningococcus bacteria. In NSW, group B causes about half of the cases of meningococcal disease, while group C is responsible for about one third of cases. Incidence of the disease is higher during winter and early spring with infants, adolescents and young adults at greatest risk.

Meningococci are spread by secretions from the back of the nose and throat of a carrier and the disease not easily spread from person to person, requiring close and prolonged contact to pass it on.


Symptoms may include:
  • sudden onset of fever
  • intense headache
  • tiredness
  • neck stiffness
  • joint pain
  • petechial rash
  • red-purple spots or bruises
  •  dislike of bright lights
  • vomiting
  • nausea

Not all symptoms may be present at once and babies or young children may have less specific symptoms. Some patients with meningococcal disease may die, despite rapid treatment.

Early detection and treatment of the disease is vital.

Those most at risk of meningococcal disease are close contacts of other cases. Notification of cases enables the Public Health Unit and staff to identify close contacts and family members at risk of infection and provide them with information and antibiotics if necessary.

Antibiotics provided for close contacts do not treat the disease, but can help stop any meningococci from spreading to others.

Epidemiology

As of 11 September 2006, there have been a total of 68 cases of meningococcal disease notified in NSW, 16 of these have been notified in South Eastern Sydney and Illawarra Area Health Service.

Serogroups responsible for area cases:
  • Group B - 6 cases
  • Group C - 2 cases
  • Unknown group - 8 cases
Age distribution of cases:
  • 0-14 years - 5 cases
  • 15-44 years - 9 cases
  • 45+ years - 2 cases

Further information

A Fact Sheet on meningococcal disease is available from the NSW Health website.
 

Recent Norovirus Gastroenteritis Activity

The South Eastern Sydney Illawarra Public Health Unit has recently received increased notifications of outbreaks of gastroenteritis, which are frequently caused by Norovirus. Noroviruses are RNA viruses that belong to the family Caliciviridae, and are a very common cause of gastroenteritis in both adults and children. During January, February and March, the Public Health Unit was notified of outbreaks of gastroenteritis at a childcare centre, a school, a hospital, a nursing home and groups of cases on board three cruise ships.

You may already be familiar with norovirus under one of its previous names:
  • Norwalk virus (after an outbreak in Norwalk, Ohio in 1968)
  • Norwalk-like virus (NLV)
  • Calicivirus
  • Small round structured virus (SRSV)
There are at least four genotypes which are further divided into a number of genetic clusters.

Epidemiology

The mechanisms of infection include:
  • direct person-to-person spread
  • aerosolisation of virus particles from vomitus
  • consumption of contaminated food or water
  • Norovirus is highly infectious. An inoculum of only ten virus particles may be enough to infect a person.

Clinical Features

The incubation period typically is 24-48 hours but can extend outside this range (12-72 hours). The clinical features are typical for a viral gastroenteritis:
  • Nausea
  • Vomiting
  • Abdominal cramps
  • Watery diarrhoea
  • Systemic features such as fever, headache and myalgia can also occur

Do not be discouraged from a diagnosis of norovirus gastroenteritis if all of these features are not present. It is quite common for a person to have a norovirus infection with only nausea.

The natural history tends to be one of complete recovery within 24-60 hours. However dehydration, amongst the very young and the elderly, may necessitate hospitalisation. Please be aware that individuals can continue to shed virus particles in their stool. Therefore it is important to emphasise to patients to continue good hygienic practices even after recovery. One study (Rockx et al) demonstrated that 26% of individuals continue to shed norovirus up to three weeks after the onset of illness.

Diagnosis is generally undertaken in specialised laboratories using either an enzyme immunoassay ora a reverse transcriptase polymerase chain reaction (RT-PCR) on stool specimens.
 

Treatment

There is no antimicrobial treatment for norovirus infections. There is no long-term immunity to noroviruses due to the heterogeneity of norovirus strains and the lack of a vaccine.
 

What to do if you suspect a norovirus gastroenteritis outbreak


Outbreaks of gastroenteritis must be notified, irrespective of the pathogen. Contact your local Public Health Unit if you have a suspected or confirmed norovirus outbreak.

Wherever possible, please collect stool specimens from sick individuals.

We cannot stress enough the importance of this!


Further Information

References


Rockx B, De Wit M, Vennema H, Vinje J, De Bruin E, Van Duynhoven Y, Koopmans M. Natural history of human calicivirus infection: a prospective cohort study. Clinical Infectious Diseases, 1 August 2002; 35(3): 246-53


Significant Increase in Ross River Virus (RRV) in Rural Areas

NSW Health has recently issued a health warning for people to protect themselves against mosquitoes, following a rise in the number of cases of Ross River Virus in parts of NSW. Ross River Virus, also known as epidemic polyarthritis, is an arbovirus spread by mosquitoes. It is thought that the recent rains and warm weather have contributed to an increase in mosquito numbers, and being holiday season means people are spending more time outside.


Transmission

Serological and laboratory studies have shown that native mammals, such as kangaroos and wallabies, are natural hosts for the virus, which is then spread to humans via mosquito bites. It has been proposed that human to human transmission via mosquitoes may also occur during periods of high activity. There are many mosquito species capable of spreading the virus, with the most common in coastal areas being the saltmarsh mosquitoes, including Aedes vigilax and Aedes camptorhynchus in northern and southern coastal regions respectively. In the urban environment, there is evidence that Aedes notoscriptus may carry the virus.


Symptoms

Whilst not life-threatening, RRV can cause persistent and debilitating symptoms in some people. These include joint aches and pain, fever, chills, headaches and sometimes a rash, which usually disappears after 7-10 days. Symptoms may continue to reappear for several months after the initial onset of illness. There is no specific treatment but people with symptoms should see their doctor. Most people fully recover in time. Ross River Virus has shown seasonal increases over the last few years, with January to March usually having the largest number of cases, although in some areas this period can be extended from November to April.



In January, 167 cases were reported across NSW, an increase of 133 cases compared to January last year, and 68 more than December 2005. Cases in the Greater Southern, Greater Western and Hunter New England Areas have accounted for 133 of these cases. The South Eastern Sydney/Illawarra Area reported 15 cases of RRV in January this year, four from the Northern Sector (South Eastern Sydney) and 11 from the Southern Sector (Illawarra). In addition there were three cases of Barmah Forest Virus (a similar virus) reported in the Illawarra area. There were no cases reported for the same period last year.


Prevention

Mosquitoes may be attracted by factors such as body odour, lack of body hair, skin temperature, the amount of carbon dioxide we excrete and chemicals produced by microbes on our skin. It has also been suggested they may be attracted by perfume and deodorants, which may account for more females than males being bitten. Pregnant women also seem to be more attractive to mosquitoes.

The best way to avoid RRV is to avoid being bitten by mosquitoes, which are most active for two hours or so either side of dawn and dusk. During these times, if you cannot avoid being outside, wear loose fitting light coloured clothes, and use an insect repellent that contains DEET or picaridin. DEET is the common name for N, N-Diethyl-m-toluamide, a chemical which disrupts the ability of biting insects to detect the source of carbon dioxide - the gas naturally given off by our skin and in our breath - which is what attracts mosquitoes and other insects to us. DEET does not kill the insects, it simply repels them. Picaridin (also known as KBR3032 or Bayrepel) is an effective alternative to DEET, which works by blocking the insect’s ability to detect you by forming a barrier on your skin. Both DEET and Picaridin offer good protection against mosquitoes if the directions are followed, and have been shown to have little or no adverse effects. Pesticide products designed to kill insects should NEVER be applied to the skin. However, if you have mozzies inside, use a knockdown insecticide, always follow the instructions, and ensure window and door flyscreens are in good repair. Check around your home for places mozzies can breed, such as saucers under flowerpots, blocked gutters, overgrown ponds and old tyres. Mosquitoes can quickly breed in very small amounts of water so regular checking is crucial for mosquito control.


Monitoring and Surveillance

The NSW Health Department funds an ongoing mosquito monitoring and virus surveillance program through the Department of Medical Entomology at Westmead Hospital. This program acts as an early warning system for virus activity by monitoring mosquito populations, viruses and weather patterns.

Local Councils are also involved in management of mosquitoes, through trapping and local monitoring of species to gain information on the potential spread of mosquito borne diseases. Some councils produce brochures and pamphlets offering information and advice on mosquito control, and these are available by phoning your local council.


More information

More Information

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