Cryptosporidiosis outbreak linked to college swimming pool

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NCAA swim meet
Amy the Nurse / Flickr cc

A collegiate swim meet was the setting for an outbreak of cryptosporidiosis after infected swimmers shared a pool while experiencing symptoms such as diarrhea, according to a study today in Morbidity and Mortality Weekly Report. Details from the outbreak highlight the transmissibility of Cryptosporidium parasites even in chlorinated pools.

The investigation started when a Massachusetts college notified the Massachusetts Department of Public Health (MDPH) that 19 of 50 members (38%) of the men's and women's swim teams had experienced diarrhea beginning 3 days after their return from a training trip to Puerto Rico earlier this year.

Competing while still having symptoms

Five and 6 days after returning from Puerto Rico, swimmers still experiencing diarrhea participated in two home meets against teams from New York and Rhode Island colleges.

Stool samples from 19 infected Massachusetts swimmers were submitted to the MDPH, which showed 13 had positive test results for Cryptosporidium. The 13 patients ranged in age from 18 to 22 years, and 8 were men. The collegiate pool was closed immediately for deep cleaning and chlorination.

No New York collegiate swimmers were infected, but two Rhode Island swimmers received positive stool Cryptosporidium test results 1 week after the swim meet.

The potential exists for sustained Cryptosporidium transmission among competitive swimmers.

"Although there was no evidence of subsequent transmission from the Rhode Island swimmers, because of the regular inter-collegiate competition and subsequent championship schedule, the potential exists for sustained Cryptosporidium transmission among competitive swimmers," the authors concluded.

Cryptosporidiosis is contracted by ingesting contaminated food and water, even chlorinated water from swimming pools. Symptoms usually self-resolve within 2 weeks, but people with weakened immune symptoms may need medical treatment.

Wastewater sampling in Canada suggests COVID case rate 19 times higher than reported

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Wastewater treatmentAt the peak of the SARS-CoV-2 Omicron variant wave in Ontario, Canada, wastewater sampling conducted before the surge suggested that COVID-19 cases were 19 times higher than reported because of changes in clinical testing, according to a study published yesterday in Emerging Infectious Diseases.

Researchers at the Regional Municipality of Peel, Ontario, led the study, which involved determining the relationship between the SARS-CoV-2 load in wastewater and COVID-19 cases and hospitalizations before the emergence of Omicron (September 2020 to November 2021) at two treatment plants in Peel.

The team used these pre-Omicron correlations to estimate the incidence of COVID-19 cases amid the Omicron surge (November 2021 to June 2022). They collected wastewater samples from the treatment plants 3 to 5 days a week, for a total of 715 samples.

In December 2021, during the Omicron BA.1 variant surge in Ontario, the province restricted clinical polymerase chain reaction (PCR) testing to high-risk people, including hospitalized patients, healthcare workers providing direct patient care, and residents and staff in hospitals and congregate living settings.

Wastewater surveillance indicators become especially relevant when PCR testing eligibility changed.

"Wastewater surveillance indicators become especially relevant when PCR testing eligibility changed or when clinical testing capacity was overwhelmed, resulting in an incomplete picture of local COVID-19 activity," the researchers wrote.

Monitoring provides crucial data beyond testing

The link between wastewater SARS-CoV-2 load and COVID-19 cases was strongest 1 day after sampling, while wastewater load and COVID-19 hospitalizations were most strongly correlated 4 days after sampling.

At the peak wastewater SARS-CoV-2 load of wave 5 on January 11, 2022, 1,160 reported COVID-19 infections were reported, compared with a predicted 7,515 cases, representing a 6.5-fold difference. At the peak of wave 6 on April 21, 2022, the estimated versus reported COVID-19 cases differed 18.7-fold (3,170 vs 170, respectively).

"The monitoring of wastewater in Peel has provided critical information about community transmission of COVID-19 that is independent of clinical testing availability and uptake," the authors wrote.

CDC signs off on tweaks to flu vaccine recommendations

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Flu shot in arm
NIAID / Flickr cc

The head of the Centers for Disease Control and Prevention (CDC), Rochelle Walensky, MD, MPH, today accepted recommendations approved last week by the Advisory Committee on Immunization Practices (ACIP) regarding the use of flu vaccines for the 2023-24 season.

One of the changes involves use of vaccines that contain updated 2009 H1N1 components. Egg-based vaccines will contain an A/Victoria/4897/2022 (H1N1)pdm09-like virus, and cell-based and recombinant vaccines will contain an A/Wisconsin/67/2022 (H1N1)pdm09-like virus. The CDC said vaccine efficacy depends on how well vaccine viruses match circulating strains, and preliminary estimates suggest that last season, vaccinated people were 40% to 70% less likely to be hospitalized due to flu and its complications.

The only other change is a tweak to recommendations for people with egg allergies. ACIP had previously recommended extra safety measures for people with severe egg allergies who receive egg-based flu vaccines, which contain a small amount of egg protein, such as ovalbumin. The committee now says, howevere, that people with egg allergies can receive any flu vaccine appropriate for their age or health status without additional safety measures beyond routine protocols.

The CDC has not changed its recommendation on flu vaccine timing. The agency notes that immunization in July and August isn't recommended unless it isn't possible to be vaccinated in September or October. Pregnant women in their third trimester can get the vaccine during the summer months to protect their babies, and children who need two doses should get their first dose as soon as doses are available.

TB vaccine receives funding for large phase 3 trial

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TB in red on x-rayThe Bill & Melinda Gates Foundation and UK-based charitable organization Wellcome announced yesterday that they will provide a combined $550 million in funding for a phase 3 trial of a vaccine to prevent tuberculosis (TB).

The phase 3 trial will assess the efficacy of the candidate vaccine—M72/ASO1E (M72)—at preventing progression from latent TB to pulmonary TB. Trial investigators aim to enroll approximately 26,000 people, including people living with HIV and without TB infection, at more than 50 trial sites in Africa and Southeast Asia.

Developed by GSK in conjunction with the Gates Medical Research Institute, the vaccine combines the M72 recombinant fusion protein, which is derived from two Mycobacterium tuberculosis antigens, with GSK's proprietary adjuvant ASO1E. In a phase 2b trial, M72 showed roughly 50% efficacy in reducing pulmonary TB in adults with latent TB.

M72 would be the first licensed TB vaccine since the bacille Calmette-Guerin (BCG) vaccine, which was developed more than 100 years ago and is effective at preventing TB in children under 5 but ineffective in adolescents and adults. It's one of 17 TB vaccines in development.

TB remains one of the world's deadliest infectious diseases.

According to the most recent data from the World Health Organization (WHO), 10.6 million people fell ill with TB in 2021 and 1.6 million died. A WHO report in December 2022 estimated that a vaccine that was at least 50% effective in preventing TB in adults and adolescents could prevent up to 76 million cases and 8.5 million deaths over 25 years, avert as many as 42 million courses of antibiotic treatment, and prevent more than $41 billion in TB-related catastrophic household costs.

"TB remains one of the world's deadliest infectious diseases," Julia Gillard, chair of the Board of Governors at Wellcome, said in a Gates Foundation press release. "The development of an affordable, accessible vaccine for adults and adolescents would be game-changing in turning the tide against TB."

Additional details on the trial design and participants will be announced in the coming months.

Global agencies release One Health research agenda for antimicrobial resistance

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The four global health agencies known collectively as the Quadripartite yesterday released a research agenda to help prevent and mitigate antimicrobial resistance (AMR) in humans, animals, agriculture, and the environment.

The One Health Priority Research Agenda for AMR contains 10 priority research areas across five themes: transmission, integrated surveillance, interventions, behavioral insights and change, and economics and policy. The agencies say the research areas were selected because they have "the greatest potential for strengthening research capacity and being the most actionable, inclusive, and impactful in the field of One Health AMR."

The priority research areas include identifying the sources and drivers of AMR between One Health sectors and which infection prevention and control practices affect the development and circulation of resistant pathogens; identifying the optimum strategies and minimum standards for establishing and maintaining integrated AMR surveillance; and identifying ways to translate and scale up the most effective One Health interventions for AMR control in settings with varying resources.

Additional priorities

Other priorities include identifying, characterizing, and assessing structural barriers to AMR-related behaviors; determining the role that communication strategies can play in promoting One Health AMR risk-reducing behaviors; and identifying the optimal financial resource strategy that will sustain support for One Health AMR interventions, particularly in low-resource countries.

The One Health research agenda comes on the heels of the World Health Organization's (WHO's) release last week of a global research agenda for addressing AMR in human health. That agenda laid out 40 research priorities across five themes.

The Quadripartite comprises the WHO, the United Nations (UN) Food & Agricultural Organization, the UN Environment Program, and the World Organization for Animal Health.

Low incidence of bacterial infections found in infants with COVID, other viral diseases

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Newborn babyA single-center study in Canada found a low incidence of bacterial infections in infants with viral infections, including SARS-CoV-2, researchers reported today in JAMA Network Open.

The study, conducted at McGill University Hospital in Montreal, sought to assess the prevalence of urinary tract infections (UTIs), bacteremia, and bacterial meningitis among febrile infants ages 8 to 60 days who were systematically tested for SARS-CoV-2 and non–SARS-CoV-2 infections. Studies have suggested that the presence of a respiratory virus in infants is associated with a decreased risk of these infections, but it's unclear whether the emergence of SARS-CoV-2 has changed this risk, and questions remain about how viral testing should guide laboratory evaluation and management.

Around 12% had UTI, bacteremia, or bacterial meningitis

A total of 931 infants were included in the analysis (median age, 38 days; 58.8% male; 46% hospitalized). Viruses were detected in 611 infants (65.6%), including 163 (17.5%) with SARS-CoV-2. Overall, 107 infants (11.5%) had UTI, bacteremia, or bacterial meningitis, and 20 (2.2%) had invasive bacterial infections (IBIs; ie, bacteremia and bacterial meningitis collectively). The prevalence of UTI, bacteremia, and bacterial meningitis was lower among infants with non–SARS-CoV-2 viruses (7.8%) compared with those with no detectable virus (20.9%), and even lower in infants with SARS-CoV-2 (3.1%).

All five infections in infants with SARS-CoV-2 were culture-confirmed UTIs. There were significantly fewer IBIs in both SARS-CoV-2 (0 of 163 infants) and non–SARS-CoV-2 groups (5 of 448 infants [1.11%]) compared with virus-negative infants (15 of 320 infants [4.69%]). All five IBIs in infants with non–SARS-CoV-2 viruses were bacteremia.

A confirmed non–SARS-CoV-2 virus should not affect the initial evaluation for young infants with fever.

"These findings support AAP [American Academy of Pediatrics] recommendations that a confirmed non–SARS-CoV-2 virus should not affect the initial evaluation for young infants with fever," the study authors wrote. "However, findings demonstrating the very low risk of IBIs among infants with SARS-CoV-2 may assist clinicians individualize management and inform shared decision-making with parents, particularly when rapid COVID-19 testing results are known or available at the point of care."

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