This month's health bulletin focuses on:
- The international transmission of monkeypox
- The recent variants in the H7N9 virus
- The resistance to the efforts of healthcare workers in the DRC
In earlier times, epidemics were often slow burns, taking months to establish as transportation was a more relaxed affair and international trips took weeks to accomplish. Despite the many advantages of our developed capabilities for rapid travel, the enthusiasm for today’s global interconnectivity is sometimes tempered by the occasional occurrence of diseases that are spread within hours from their origin to countries thousands of miles distant. At the beginning of the outbreak of the SARS virus in 2003, for example, a poorly patient checking-in to the Metropole hotel in Kong Hong on the 21st February, inadvertently infected an elderly woman who had returned to Toronto by the 23rd February, sparking off a series of SARS infections that was to take 4 months to control.
A more recent example of international transmission is that of monkeypox, acquired in Nigeria and spread to Singapore this month. Monkeypox is a virus that can produce a range of clinical conditions, from rashes and flu-like fevers, to severe bacterial infections and inflammation of the brain.
This is the fourth time that the on-going monkeypox outbreak in Nigeria has spread outside of its borders. In 2018, 3 international travellers were infected, taking the virus to the UK and Israel. The Singaporean case is reported to have occurred in someone attending a workshop: 18 of his fellow delegates have just finished 21 days of quarantine. These fellow attendees who were at high risk of having been infected were all treated with the smallpox vaccine as it can be effective in up to 85% of patients if used early enough. Luckily, all close contacts of the patient failed to show any sign of the disease.
Although the Nigerian patient is still admitted at the National Centre for Infectious Disease in Singapore, he is said to be doing well.
Many fear that the next widespread global infection, the so-called pandemic, will be an avian influenza. Although we have had several novel bird flus in the last few years, their transmission between humans has been luckily poor, which has meant that an epidemic was unlikely to occur.
Of the recent pandemic flu candidates, the H7N9 flu was perhaps the most concerning. As its human to human transmission is also poor, as long as the virus does not mutate significantly, outbreaks cannot occur. Recent reports are showing that the make-up of the H7N9 virus is changing however.
There have been 5 waves of the H7N9 virus charted since its emergence in China in 2013. As an avian flu, its primary host was poultry. Originally producing few symptoms in chickens, this virus would sometimes infect humans to serious effect. As successive iterations of infections have progressed, the characteristics of the virus have changed. The recent variants can now cause severe disease in chickens; the virus being described as a highly pathogenic (disease causing) avian influenza. As this change has only been happening over the last few seasons, at present we do not know the full extent of its affects on humans. There is some evidence that although the symptoms may be similar between the two variants, the case fatality rate of the recent variant may be higher. Importantly, the influenza had previously shown some sensitivity to an antiviral treatment with oseltamivir, this sensitivity is now waning. Furthermore, we don’t know if the ability of humans to pass the virus on to other humans has been effected – we think not. Those at risk of the virus are still those who come into close contact with infected chickens and their carcasses – poultry farmers and the like. Once humans are infected, passing the infection to another human is difficult. This might be the case with the highly pathogenic strain as well. The virus seems to be on the move, however, whether human to human transmission will remain low is at present unknown.
- 5 waves of the H7N9 virus since its emergence in China in 2013
- Characteristics of the virus have changed
- Recent variants can now cause severe disease in chickens
- Full extent of affect on humans unknown
- Influenza sensitivity to antiviral treatment oseltamivir waning
Democratic Republic of Congo (DRC)
As the number of Ebola cases exceeds 2,000 in the DRC, there has been a slight improvement in the numbers of newly infected individuals. Many interpret this with caution, however, as there have frequently been delays in the notification of new cases. More than 1,300 people have now died from Ebola during this outbreak, the second largest in history.
It is a truism that control of previous epidemics has usually been presaged by increasingly accurate mapping of transmission routes. What this means is that how patients have become infected, and who they might have subsequently infected, becomes known – allowing for quarantine and vaccination of those potentially exposed, limiting further transmission to others. During this epidemic, in many instances it is still unclear how patients have become exposed to the virus. Until recently, up to 80% of infections lay outside of known transmission groups. Until this percentage reduces, control of the outbreak is unlikely to be achieved.
The attacks on Ebola treatment centres have been widely reported: 174 raids have occurred in the first half of this year; a three-fold increase compared to the previous 6 months. In fact there have been reports that in some areas workers are reticent to wear personal protective equipment - the gowns, gloves and masks that help to protect against the virus - as that would potentially mark them out for retribution from armed militia. Closing the annual World Health Assembly in Geneva this week, the WHO director general stated that attacks on Healthcare workers in the field were recently an almost daily occurrence.
What has been perhaps less reported is the increased resistance of the DRC nationals to the efforts of healthcare workers in the field. As in previous outbreaks, the trust of the local population is not easily won, replaced instead with fear and distrust that have often fuelled acts of violence towards those who are there to help. Only a few days ago, a tragic example of this is the killing of a healthcare worker by villagers of Vusahiro in the Mabalako region of Eastern DRC.
With the many difficulties in containing the ongoing epidemic, many have thought it inevitable that spread to a neighbouring country would occur. Certainly, the challenge of detecting cases before they were able to cross DRC’s several border points is truly immense. Of the 61 million screenings performed since its instigation, only 9 cases of Ebola have been detected. It is clear that screening for Ebola is attempting to detect needles in haystacks, but so far seemingly successfully. As the positivity rate is so vanishingly small, the possibility of missing a true positive case seems to be certain, as long as the case numbers continue to rise and the turbulence of the population is fuelled by fear and desperation.