Poliomyelitis outbreak in Papua New Guinea: health system and health security implications for PNG and Australia

Investigating the mechanism of Echovirus 30 cell invasion

Viruses invade susceptible cells through a complex mechanism before injecting their genetic material into them. This causes direct damage to the host cell, as well as resulting in disease in the corresponding system. Echovirus type 30 (E30) is a member of the Enterovirus B group and has recently been reported to cause central nervous system (CNS) disorders, leading to viral encephalitis and viral meningitis in children. In this review, we aim to help in improving the understanding of the mechanisms of CNS diseases caused by E30 for the subsequent development of relevant drugs and vaccines.

Vaccines and Senior Travellers

Background: International tourist travel has been increasingly steadily in recent years, and looks set to reach unprecedented levels in the coming decades. Among these travellers, an increasing proportion is aged over 60 years, and is healthy and wealthy enough to be able to travel. However, senior travellers have specific risks linked to their age, health and travel patterns, as compared to their younger counterparts.

Methods: We review here the risk of major vaccine-preventable travel-associated infectious diseases, and forms and efficacy of vaccination for these diseases.

Results: Routine vaccinations are recommended for older persons, regardless of whether they travel or not (e.g., influenza, pneumococcal vaccines). Older individuals should be advised about the vaccines that are recommended for their age group in the framework of the national vaccination schedule. Travel-specific vaccines must be discussed in detail on a case-by-case basis, and the risk associated with the vaccine should be carefully weighed against the risk of contracting the disease during travel. Travel-specific vaccines reviewed here include yellow fever, hepatitis, meningococcal meningitis, typhoid fever, cholera, poliomyelitis, rabies, Japanese encephalitis, tick-borne encephalitis and dengue.

Conclusion: The number of older people who have the good health and financial resources to travel is rising dramatically. Older travellers should be advised appropriately about routine and travel-specific vaccines, taking into account the destination, duration and purpose of the trip, the activities planned, the type of accommodation, as well as patient-specific characteristics, such as health status and current medications.

Surveillance strategies for the detection of disease outbreaks in the Pacific islands: meta-analysis of published literature, 2010-2019

OBJECTIVE

Due to their tropical location, development status and the limited capacity of health systems, Pacific island counties and territories are particularly susceptible to infectious disease outbreaks; but evidence as to the optimal way in which outbreaks are detected is scarce. In this review, we synthesise evidence from literature about how outbreaks are detected in Pacific island countries and territories and critique factors identified as inhibiting surveillance practice.

METHOD

For this systematic review, we searched electronic databases Embase, Global Health, MEDLINE and MEDLINE Epub from 1 January 2010 and 31 March 2019 for reports describing infectious disease outbreaks occurring in the Pacific islands. Reports were included if they reported the method by which an outbreak was detected or the time between an outbreak's onset and its detection. We extracted information about the report type and authors, the outbreak and its method/s of detection, and pertinent issues inhibiting surveillance practice.

RESULTS

Of 860 articles identified, 37 reports describing 39 outbreaks met the inclusion criteria. Most outbreaks (n = 30) were identified through formal event-based surveillance; six through syndromic surveillance; and two by ad hoc notification from the community. Barriers to early outbreak detection included population isolation; lack of resources and infrastructure to support surveillance implementation and signal investigation; and broader health system factors such as preparedness planning and availability of laboratory services.

CONCLUSION

Most surveillance-related gain in the Pacific islands may be made through building formal event-based surveillance systems and streamlining reporting processes to facilitate outbreak notification. This observation is pertinent given the focus on establishing and expanding syndromic surveillance approaches for outbreak detection in the islands over the last decade.

Epidemic poliomyelitis, post-poliomyelitis sequelae and the eradication program

Epidemics of paralytic poliomyelitis (polio) first emerged in the late 19th and early 20th centuries in the United States and the Scandinavian countries. They continued through the first half of the 20th century becoming global. A major epidemic occurred in Australia in 1951 but significant outbreaks were reported from the late 1930s to 1954. The poliovirus is an enterovirus that is usually transmitted by the faecal–oral route but only one in about 150 infections results in paralysis when the central nervous system is invaded. The Salk inactivated polio vaccine (IPV) became available in Australia in 1956 and the Sabin live attenuated oral polio vaccine (OPV) was introduced in 1966. After decades of stability, many survivors of the earlier epidemics experience late-onset sequelae including post-polio syndrome. The World Health Organization launched the global polio eradication initiative (GPEI) in 1988 based on the easily administered OPV. The GPEI has resulted in a dramatic decrease in cases of wild polio so that only Pakistan and Afghanistan report such cases in 2020. However, a major challenge to eradication is the reversion of OPV to neurovirulent mutants resulting in circulating vaccine-derived poliovirus (cVDPV). A novel, genetically stabilised OPV has been developed recently to stop the emergence and spread of cVDPV and OPV is being replaced by IPV in immunisation programs worldwide. Eradication of poliomyelitis is near to achievement and the expectation is that poliomyelitis will join smallpox as dreaded epidemic diseases of the past that will be consigned to history.