The Iowa Department of Health and Human Services (IDHHS) today announced the death of a middle-aged eastern Iowa resident from Lassa fever, a rare viral hemorrhagic fever that can be transmitted among humans through infected body fluids.

In a statement, officials said the individual had recently traveled to West Africa, where they are thought to have contracted the virus. Initial testing was conducted at the Nebraska Public Health Laboratory, and confirmation testing is under way at the US Centers for Disease Control and Prevention (CDC).

State working with partners on contact tracing

The patient was receiving treatment at the University of Iowa Health Care, and state health officials are working with the CDC and local partners to identify contacts.

“This is a difficult time for the family of this individual and I want to express our deepest condolences,” said Robert Kruse, MD, MPH, state medical director at he IDHHS. “I want to assure Iowans that the risk of transmission is incredibly low in our state. We continue to investigate and monitor this situation and are implementing the necessary public health protocols.”

The United States has now reported eight travel-related Lassa virus cases over the past 55 years. The country reported its last imported case in 2015 in a person returning from Liberia to New Jersey.

Lassa fever is typically transmitted by rodents, and though most human illnesses are mild or moderate, infections are deadly in about 1% of cases. Causing as many as 300,000 cases each year, the virus is endemic in parts of West Africa. In July, an expert group led by the Center for Infectious Disease Research and Policy (CIDRAP) raised concerns about the slow pace of treatments of vaccines for Lassa virus and published a roadmap to address the growing threat.

In updates over the last 3 days, Rwanda’s health ministry has reported one more Marburg virus case.

The most recent patient is a contact of an earlier identified patient, the ministry said in an October 26 update. The country now has 65 cases, of which 15 were fatal. In an update today, officials said three people are currently in treatment for their infections.

The country had reported two cases a few days earlier, one of whom is a health worker, and the other has links to the site where the index patient was exposed, a cave in a mining area that harbored fruit bats known to carry the virus.

After the identification of the index case in late September, nearly all cases that followed involved healthcare workers at two hospitals in Kigali. However, the two most recent cases appear to involve people from the community who were under monitoring. 

For the first time in 20 years, the United States recorded locally acquired malaria cases last year. A report published late last week in Morbidity and Mortality Weekly Report details the 10th US case, in Arkansas. The previous cases were in Florida, Texas, and Maryland.

Since the 1970s, cases of travel-associated malaria have ticked upward in the United States, with 2,048 such cases recorded in 2019 by the Centers for Disease Control and Prevention (CDC). 

The authors explained the Anopheles mosquito species present across the United States can acquire Plasmodium infection from patients with travel-associated malaria. The mosquitoes can then transmit the parasite to people who haven't traveled.

No travel history

In September of 2023, a resident with no travel history in Saline County, Arkansas, was hospitalized after 10 days of illness. In addition to no recent travel, the person had no record of blood transfusion, organ transplant, or other bloodborne pathogen exposure. 

Blood-count analysis was suggestive of malaria, and a pathologist's review of thick and thin blood smears verified the presence of Plasmodium vivax/Plasmodium ovale gametocytes. This finding was later confirmed by the CDC.

Although the risk for locally acquired malaria in the United States remains very low, its reemergence highlights the importance of vectorborne disease preparedness and response efforts.

"As of September 2024, no additional autochthonous malaria cases had been identified in Arkansas," the authors said. "Although the risk for locally acquired malaria in the United States remains very low, its reemergence highlights the importance of vectorborne disease preparedness and response efforts."

• San Diego County health officials said last week that they are investigating a second locally acquired dengue infection, this time in a Vista resident who was hospitalized. The county’s vector-control department is treating the area around 60 homes in Vista, which is about 42 miles north of San Diego. The county reported its first case on August 6, which involved a resident of Escondido. Over the past several weeks, Los Angeles County has reported nine locally acquired dengue cases, including a cluster of six in Baldwin Park.
• Mauritius on October 26 announced its first mpox case, which involves a 49-year-old man who had traveled from Nigeria, according to a government announcement translated and posted by FluTrackers, an infectious disease news message board. The patient is being treated in isolation at a hospital in Port Louis. The report didn’t note the clade of the virus. The country’s case brings the number of African nations reporting mpox cases this year to 19.
• The Coalition for Epidemic Preparedness Innovations (CEPI) today announced a $1 million grant to support work by Abera Bioscience to see if its bacteria-based platform can boost mucosal immunity of an intranasal vaccine being developed as a next-generation vaccine to respond to epidemic and pandemic threats. The platform involves bacterial outer-membrane vesicles, noninfectious particles that some bacteria release that are known to boost immunity.