The Pan American Health Organization (PAHO) recently issued an epidemiological alert for rising Oropouche virus infections, urging countries to step up surveillance amid spread to new areas, reports of the first deaths, and suspected maternal transmission.

Oropouche virus is typically spread by a species of biting midge called Culicoides paraensis, but multiple factors including climate change, deforestation, and urbanization have contributed spread beyond Brazil's Amazon region to countries that haven't reported cases before, including Bolivia and Cuba.

Since the first of the year, 8,078 cases have been reported from five countries, mostly from Brazil. The others include Bolivia, Peru, Colombia, and Cuba. Two deaths have been reported, both from Brazil. Both of the fatal cases occurred in young women who didn't have underlying health conditions.

Brazilian officials are investigating a link between Oropouche virus and poor fetal outcomes. So far, the country has reported one fetal death, a miscarriage, and four newborns with microcephaly. The country is also investigating three more possible cases of maternal transmission, all involving fetal deaths reported from Pernambuco state. In one of the three cases, the Oropouche virus genome was detected in fetal tissue and blood samples.

In an updated risk assessment, PAHO said the investigation into the rise in activity is still underway and the trajectory is unknown. However, it upgraded the risk for the region to high based on a moderate level of confidence.

European countries report 10 imported cases

In a related development, three countries in Europe have now reported 10 imported Oropouche virus cases, the European Centre for Disease Prevention and Control (ECDC) said in its latest weekly communicable disease update. Italy and Spain had reported earlier cases, and now Germany has also reported two similar illnesses. Nine cases involved people who visited Cuba, and one person had traveled to Brazil. 

The ECDC said the risk to European travelers is low if they protect themselves from midges or mosquitoes that spread the virus. It also added the risk of local spread in Europe is low, due to the absence of competent vectors.

Cambodia's health ministry on August 3 announced a second human H5N1 avian influenza in less than a week, which involves a 16-year-old girl who is hospitalized in serious condition, according to a statement translated and posted by Avian Flu Diary, an infectious disease news blog. 

The girl is from the same province (Svay Rieng), but a different town, as a case announced earlier in the week.

About 4 days before her symptoms began, she touched and held dead chickens that died at her house and her neighbor's house. The girl's illness marks Cambodia's ninth case this year. So far, the clade isn't known, but the country's earlier cases were linked to an older 2.3.2.1c clade that circulates in some Asian countries, including Cambodia. 

Since early 2023, Cambodia has reported a rise in H5N1 infections, which are often severe of fatal. The country has now reported 15 cases since February 2023.

The US Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) has confirmed three more H5N1 avian influenza outbreaks in dairy cattle, raising the national total to 181 from 13 states.

The latest confirmations are from Colorado, South Dakota, and Texas. 

In other updates, APHIS also reported more detections in wild birds in mammals. The group reported about more than 100 more H5N1 detections in wild birds across several states. Some were waterfowl taken by hunters and were sampled last fall. However, several were agency-harvested birds from Colorado's Weld County, which has been a recent hot spot for dairy cow outbreaks, poultry outbreaks, and human illnesses. Species in Weld County that tested positive included doves, sparrows, starlings, and pigeons.

Regarding mammals, APHIS over the past few days has reported 27 more detections, raising its confirmed number to 373. Most of the newly confirmed positives involve deer mice and house mice from Weld County in Colorado. The group also included three domestic cats from Larimer County in Colorado, plus a rabbit and a vole from Weld County. 

A single-center study found that giving hematopoietic stem cell transplant (HSCT) recipients preventive doses of oral vancomycin was associated with a significant decrease in the risk of Clostridioides difficile infection (CDI), researchers reported today in Antimicrobial Stewardship & Healthcare Epidemiology.

Because of their immunocompromised state, HSCT patients have a nine-fold increased risk of CDI compared with the general population. To reduce this risk, the bone marrow transplant team at Robert Wood Johnson University Hospital (RWJUH) in New Jersey implemented a protocol in December 2019 for universal oral vancomycin prophylaxis (OVP) for all patients undergoing HSCT. Prior to this protocol, the decision to use OVP was made by the provider and was not routine.

To assess the effectiveness of the OVP protocol, researchers with RWJUH and Rutgers University reviewed the medical records of all HSCT patients admitted from January 2015 through August 2022. The primary end point was the incidence of in-hospital CDI. Secondary endpoints included incidence of vancomycin-resistant enterococci (VRE) and gram-negative bloodstream infections, hospital survival, and length of hospital stay.

Promising results, but clinical trials needed

A total of 156 HSCT patients met inclusion criteria, with 75 in the pre-universal prophylaxis era (no OVP) and 81 in the post-universal prophylaxis era (OVP). The most common indicators for transplant were multiple myeloma, acute myeloid leukemia, and Hodgkin lymphoma. Among the 81 patients in the OVP group, there was 1 (1.23%) case of CDI, compared with 8 (10.67%) of 75 in the no OVP group. No positive VRE cultures were found in either group. There were no significant between-group differences in the incidence of gram-negative bloodstream infections, hospital survival, and length of stay.  

"These findings are promising considering infections such as CDI are among the most common complications affecting HSCT patients," the study authors wrote. But they caution that more research is needed to better understand the potential implications of using OVP on HSCT patients' enteric microbiota, increased VRE colonization, and the risk of the emergence of vancomycin-resistant C difficile strains.

"Prospective clinical trials and cost-effectiveness studies are needed to more definitively assess the safety and efficacy of this practice," they concluded.

These findings are promising considering infections such as CDI are among the most common complications affecting HSCT patients.