An Australian state has recorded a decline in gastrointestinal diseases during the period measures were in place to control the coronavirus pandemic.

The study covered communicable disease surveillance in Central Queensland for six months after the introduction of physical distancing and wider lockdown measures in Queensland.

Data from April to September 2020 was compared with the average for the same months during the years 2015 to 2019. Findings were published in the Communicable Diseases Intelligence journal.

Noticed decline
In the six-month period, reports decreased compared to the five year average for cryptosporidiosis from 40 to five in 2020 and Yersiniosis was down from 15 to eight patients.

The five year average for campylobacteriosis was 158, which fell to 145 in 2020. Salmonellosis also dropped from the average of 122 to 90 in this past year. Shigellosis went up from the five year average of four to eight in 2020.

The 2015 to 2019 average for Shiga toxin-producing E. coli (STEC) was one and only a single infection was recorded in 2020. only two cases of Hemolytic uremic syndrome (HUS) had been reported in the past five years but two were also seen in 2020.

Limitations of the work include a potential decline in seeking healthcare by people fearful of exposure to patients with COVID-19. Also, the report says there might have been a reduction in testing for other communicable diseases because of high numbers of COVID-19 test requests.

It suggests the wider lockdown, overseas travel restrictions, social and physical distancing and hygiene etiquettes may have contributed to the reduction in transmission of cryptosporidiosis and other diseases in Central Queensland.

“Long term investigation into pattern of disease notifications may provide additional information on the impact of the implemented measures on notifiable diseases in Central Queensland,” said researchers.

An earlier analysis in Australia found diseases, including foodborne infections, declined after public health measures were introduced because of the pandemic.

Norovirus in Victoria
Another study, published in the same journal, found a reduction in enterovirus and norovirus infections during the pandemic in a different Australian state.

Researchers examined referral data for enteroviruses and noroviruses in Victoria. Fecal specimens from gastroenteritis outbreaks are referred to the Victorian Infectious Diseases Reference Laboratory (VIDRL) to test for the presence of noroviruses.

The enterovirus specimen positivity rate was down by 84.2 percent in 2020 compared to the previous decade, while the norovirus outbreak positivity rate declined by 49 percent.

Norovirus outbreak referrals for 2020 were down beginning in March compared to 2010 to 2019, but the positivity rate reduced sharply from April onwards, with only one outbreak identified from May to September, coinciding with the initial high-level restrictions.

From January 2010 to September 2020, VIDRL received fecal specimens from 2,582 gastroenteritis outbreaks for norovirus testing, of which 1,585 had norovirus RNA detected in at least one specimen.

In 2010 to 2019, the average number of norovirus outbreaks referred each year from January to September was 183.3, but in 2020 it declined to 51. The norovirus positivity rate reduced from an average of 61.5 percent of outbreaks in January to September 2010 to 2019, to an average of 31.4 percent in 2020.

Norovirus showed a significant reduction in incidence in Victoria in 2020 compared to the previous decade, according to the study.

“The most likely explanation is the concurrence of social restrictions, physical distancing, personal hygiene awareness and international and domestic border closures resulting from the COVID-19 pandemic in 2020. It remains to be seen whether infectious diseases, other than COVID-19, increase in incidence when restrictions are eased,” said researchers.