Report describes 4 cases of deer-to-human TB transmission in Michigan

News brief
Deer in snow
Marcel Holyoak / Flickr cc

Yesterday in Clinical Infectious Diseases, scientists report on four people in Michigan who contracted tuberculosis (TB) linked to wild deer and domestic cattle from 2019 to 2022, raising the total number of zoonotic cases in the state to seven since 2002.

A team led by physicians at Corewell Health East and the University of Michigan reviewed data and Mycobacterium bovis  cultures from the Michigan Department of Health and Human Services TB database. They conducted interviews and compared whole-genome sequences of human isolates with a veterinary library of M bovis strains.

The study authors noted the 1994 identification of M bovis cases in wild deer in northern lower Michigan in 1994, with  transmission to local cattle. From 2002 to 2017, M bovis infections in three deer hunters were reported in the state.

Continued spread among humans, animals

The three confirmed and one probable human M bovis cases identified from 2019 and 2022 resulted in cutaneous disease, two cases of severe pulmonary disease, and one case of human-to-human spread. Those infected were a taxidermist, a woman who interacted with deer in the affected area, and a man with no obvious animal exposures and his female household contact. The three human isolates had zero to three mutations linked to M bovis strains circulating in local deer and cattle.

Future studies should examine the routes of transmission and degree of risk to humans through expanded epidemiological surveys.

The authors said M bovis continues to spread from deer to humans and cattle and poses a particular risk to people with weakened immune systems.

"Future studies should examine the routes of transmission and degree of risk to humans through expanded epidemiological surveys," they wrote. "A One Health approach linking human, veterinary, and environmental health should address screening for TB infection, public education, and mitigation of transmission."

M bovis is usually tied to TB in cattle, which can transmit the bacteria to humans through consumption of unpasteurized dairy products. The bacteria cause disease that is indistinguishable from that caused by M tuberculosis, and common diagnostic tests can't identify M bovis, the authors said.

Study: Nearly half of bloodstream infection isolates from transplant recipients were multidrug-resistant

News brief

A study of patients at a transplant center found a high burden of bloodstream infections (BSIs) caused by multidrug-resistant organisms (MDROs) following organ transplant, researchers reported yesterday in JAC-Antimicrobial Resistance.

To describe the epidemiology of BSIs in the year after solid organ transplant (SOT), researchers at Houston Methodist Hospital analyzed data on patients who received kidney, liver, heart, and multi-organ transplants from June 2016 to September 2021. They examined BSIs that occurred within a year of the transplant and classified MDRO phenotypes for Staphylococcus aureus, enterococci, Enterobacterales, Pseudomonas aeruginosa, and Candida spp. They also compared BSI characteristics between SOT types and determined risk factors for 90-day mortality.

Substantial proportion of isolates multidrug-resistant

Of the 2,293 patients (54.6% kidney, 28.9% liver, 9.6% heart, and 7.0% multi-organ transplant) included in the study, 8.5% developed BSIs, which were most common after multi-organ (23.1%) and liver (11.3%) transplants. Among 196 patients with BSI, there were 313 BSI episodes, yielding 323 unique isolates, 45.5% of which were MDROs.

Liver transplant recipients harbored the most MDROs (53.4%), followed by multi-organ transplant recipients (49.4%). The most frequent MDROs were vancomycin-resistant enterococci (VRE) (comprising 69.8% of enterococci) and extended-spectrum beta-lactamase–producing and carbapenem-resistant Enterobacterales (CRE) (29.2% and 27.2% of Enterobacterales, respectively). Overall mortality after BSI was 9.7%, but VRE was the only MDRO independently associated with an increase in mortality (adjusted odds ratio, 6.0; 95% confidence interval, 1.7 to 21.3).

The study authors say that while the BSI incidence was lower than found in a recent study conducted in Denmark, the substantial proportion of MDROs and the number of patients with more than one BSI episode are concerns.

"Although BSI incidence was lower than in previous studies, the emergence of MDR phenotypes, especially CRE and VRE infections after liver and multi-organ transplantation, is worrisome," they wrote. "Our results can guide future research on strategies to decrease burden and impact of MDROs after SOT."

Indonesia reports more vaccine-derived polio cases

News brief

In December, Indonesia's health ministry reported two more cases of circulating vaccine-derived poliovirus type 2 (cVDPV2) cases, raising its total since October 2022 to six, the World Health Organization (WHO) said yesterday.

polio virus
NIAID/Flickr cc

One of the patients is a 6-year-old girl from Central Java province who had recently traveled to Madura Island in East Java province. Her acute flaccid paralysis symptoms began on November 21. She had received two doses of bivalent oral polio vaccine. Genetic sequencing suggests her infection is related to a virus that was identified in a previous case in West Java province in March 2023.

The other patient is a 1-year-old boy from Madura Island in a district that neighbors the one the girl had visited. His paralysis symptoms began on November 22, and he had received four doses of bivalent oral polio vaccine.

Some areas where recent cases were reported have suboptimal vaccine coverage. The WHO said there are no hard-to-reach areas, but sociocultural barriers on Madura Island contribute to vaccine hesitancy, including fear of adverse effects and of multiple injections, and sometimes religious reasons.

Of the Indonesia's four other cases reported since October 2022, three were in Aceh province, with the other in West Java. Detection of cVDPV2 in at least two different sources at least 2 months apart, both with genetic links, shows evidence of community transmission, the WHO said. The agency added that Indonesian officials are conducting active case finding and are boosting efforts to shore up immunization uptake. And, based on the government's request, the WHO has approved the release of 20 million doses of novel oral polio vaccine type 2, the next-generation vaccine designed to curb outbreaks involving cVDPV2.

Three African countries report more cases

In other polio developments, three African countries reported more polio cases, all involving cVDPV2, according to the latest update from the Global Polio Eradication Initiative. All are included in the country totals for 2023.

Guinea reported 3 cases in two provinces, raising its total for the year to 34. Mozambique reported 1 case, in Manica, which marks the nation's first case of 2023. Nigeria reported two 2 cases in Kano, raising the country's 2023 total to 64.

This week's top reads