By Carol A. Kemper, MD, FIDSA
Visceral Larva Migrans from Baylisascariasis
Source: Vaughan AM, Kamel D, Chang M, et al. Baylisascariasis (raccoon roundworm infection) in two unrelated children — Los Angeles County, California, 2024. MMWR Morb Mortal Wkly Rep. 2025;74(28):444-449.
In September 2024, an adept clinician in Los Angeles reported two possible but unrelated cases of eosinophilic meningoencephalitis from Baylisascaris procyonis in a 14-year-old teenager and a 15-month-old child. The teenager had a diagnosis of autism spectrum disorder and a history of pica. He developed one week of progressive confusion and unsteady gait, with mild peripheral eosinophilia (14%), and eosinophilia in cerebrospinal fluid (CSF) (15%). Brain magnetic resonance imaging showed numerous enhancing lesions, and an ocular examination revealed a live nematode in the eye. This was treated with laser ablation, and he received six weeks of albendazole and steroids. Because the clinician had some familiarity with the diagnosis, the child was able to be treated promptly and recovered. Using a Centers for Disease Control and Prevention (CDC) immunoblot assay, serum was weakly positive for B. procyonis antibodies, but CSF was negative, a pattern that has been observed previously in similar infections.
The second child, a healthy 15-month-old, was repeatedly hospitalized for lethargy, weakness, gait instability, and progressive encephalopathy in June 2024. Studies showed peripheral eosinophilia (53%) and eosinophilia of the CSF pleocytosis (16%). Brain imaging showed white matter “abnormalities,” and he was diagnosed with acute disseminated encephalomyelitis. Eventually, admission to a third hospital, where the child described earlier had been treated, prompted concerns for the same diagnosis. An eye exam showed a live nematode, and the child received laser ablation and six weeks of albendazole and steroids, similar to the previously mentioned case. Unfortunately, he remained severely neurologically impaired, requiring a g-tube for feeding. At the CDC, serum was weakly positive for B. procyonis antibodies, but the CSF was negative.
These two cases prompted investigation by the Los Angeles County Public Health Department (LACPHD). Both residences were inspected, and a “raccoon latrine” was found on the roof of the back door for the first patient described earlier. Raccoons frequented the property. LACPHD immediately recommended removal of the latrine. Neighbors routinely left food out for cats, and raccoons remained a persistent problem. No source for infection was found for the second case, although the parents said the child had been seen to put dirt and bark in his mouth in the backyard, at the beach, and at local parks.
Although I always think of Angiostrongylus when considering eosinophilic meningoencephalitis, clinicians should consider migrating Baylisascaris larvae as another important cause, especially in young children or children with developmental delay or pica, who are at higher risk for this infection.
LACPHD launched a broader investigation and educational campaign within an eight-block area of the first child’s residence, visiting 476 households and 35 child care centers. Educational materials were left at every home, including the importance of keeping raccoons away from the property, removing raccoon latrines, and seeking prompt diagnosis of symptomatic children. They also provided recommendations to local veterinarians to perform annual fecal examination for domestic pets, especially dogs.
Raccoons are very clean, social animals, and they preferentially defecate in a designated communal location, called a raccoon latrine, which can be located at the base of a tree or a tree stump, on a shed roof, or in an unsecured attic space. Raccoon feces may contain the eggs of B. procyonis, which take two to four weeks to mature and become infectious outside the gut. The eggs are very hardy and can persist in soil for months or years. Property owners should take measures to discourage raccoons, removing any outdoor pet food or food sources, keeping garbage lids closed, securing attics and crawlspaces, and removing feces. One website even recommended torching the soil of a raccoon latrine with a propane torch to destroy the eggs. Sandboxes should be kept clean and covered when not in use. Back when I had a hot tub in the back yard, the neighborhood raccoon family (euphemistically called a “gaze” or a nursery of raccoons) would congregate there every night, somehow lift the hot tub lid off the tub, wash their food, and enjoy a communal meal. They destroyed so many lids, I finally had to get rid of the hot tub.
B. procyonis eggs are infectious to domestic pets, especially dogs, which can act as a definitive but less than optimal host, so they often have lower worm burden and fewer eggs in their feces. Dogs can rarely develop visceral, ocular, and central nervous system involvement from migrating larvae. I was fascinated to read that domestic chickens also can be infected. Chickens have their own species of roundworm, called Ascaridia galli, which does not cause visceral larva migrans in chickens. But chickens are an “aberrant host” for B. procyonis, meaning the larvae do not complete their life cycle in a chicken but continue to migrate throughout the body, leading to blindness and extensive neurologic symptoms (head tilt, ataxia, rigors, and paralysis). Anyone with domestic chickens knows how hard it is to keep raccoons away.
Measles Testing of Persons with HIV
Source: Andrews HS, Blanchard HL, Yang S, Utay NS. Low rate of documented measles immunity in a large urban HIV clinic. Clin Infect Dis. 2025;May 28:ciaf278. doi:10.1093/cid/ciaf278. [Online ahead of print].
Measles immunity generally is presumed based on age (birth prior to 1957); prior receipt of two measles, mumps, rubella (MMR) vaccines; or documentation of measles immunoglobulin G (IgG) serology. Detection of measles-specific IgG antibody by enzyme-linked immunosorbent assay (ELISA) is a standard means to confirm serologic immunity, although some might argue that detection of cell-mediated immunity using the more tedious plague-reduction neutralization assay more directly correlates with true immunity.
Persons with human immunodeficiency virus (HIV) infection (PWH) are at increased risk for more severe measles infection, especially those with lower CD4 cell counts. Earlier reports suggested that mortality for measles infection in acquired immunodeficiency syndrome (AIDS) may be as high as 40%. Earlier seroprevalence studies observed serologic immunity in 70% to 92% of PWH, but younger immigrants may be at particular risk for inadequate immunity. Previously, such individuals were relatively protected from measles infection by high levels of immunity in the general public. But as vaccine rates fall, this community protection is no longer a given, and the recent measles outbreak in Texas increased concern for those with HIV.
As a result, clinicians at a large urban Dallas County, TX, HIV clinic performed a retrospective review of presumed measles immunity of persons attending a large Ryan White-supported clinic system from 2015-2025. Any adult ≥ 18 years of age who had been seen in the clinic at least once was included in the review. Records were assessed for birth prior to 1957, documentation of at least one dose of MMR, and documentation of serologic test results. Demographic and clinical characteristics were collected for those with documentation of measles serologic testing.
Only 1,531 of 13,622 (11.2%) patients had documentation of presumed measles immunity, including 6.6% born before 1957, 3% with a documented dose of MMR, and 1.9% with a confirmed measles IgG antibody. Serologic testing had been performed in 311 individuals, with a positive result in 253 (82%). A negative serology was associated with younger age, Hispanic ethnicity, birth in Latin America, and a history of AIDS-related malignancy. However, in multivariate analysis, predictors of seronegativity were age ≤ 35 years, being white, and a CD4 count < 200 cells/microliter. Of those 34 individuals with a negative serology and eligibility for measles vaccination (CD4 counts > 200 cells/microliter), only 10 (29%) had received vaccination.
The authors recommend verifying measles immune status for any PWH attending your clinic. If vaccine records cannot be confirmed, consider adding a measles IgG serology to their next routine testing. Given how many PWH may have existing immunity, a strategy of first testing and confirming immunity, with selective vaccination of eligible seronegative patients with CD4 counts ≥ 200 cells/microliter second, is appropriate.
Ambulatory Glucose Monitoring a Risk for Bloodborne Pathogens
Source: Moore JR, Breeyear T, Gowler CD, et al. Notes from the Field: Hepatitis B virus transmission associated with assisted blood glucose monitoring in a skilled nursing facility — North Carolina, 2024. MMWR Morb Mortal Wkly Rep. 2025;74(29):463-464.
In May 2024, the North Carolina health authorities received a report of acute hepatitis B virus (HBV) infection in a 69-year-old with diabetes, who was a relatively new resident of a local skilled nursing facility for 10 months. This report prompted an investigation for potential exposures and assessment of infection prevention practices in the facility. The Centers for Disease Control and Prevention (CDC) recommends assigning one glucometer to one individual and not sharing when possible. If a device must be shared, there are specific manufacturer recommendations for cleaning and disinfection with every use.
Investigation of the facility found no observed gaps in infection prevention practices, although glucometers were shared between residents and disinfected between uses. No resident of the facility was known to have HBV infection. The next step was to screen all residents of the facility for HBV infection, including HBV deoxyribonucleic acid (DNA). This revealed one individual with previously diagnosed but unreported chronic HBV infection who also had diabetes and roomed a few doors away from the index case. Whole genome sequencing confirmed the two strains for both residents were identical.
Both individuals were routinely monitored using two devices held on a cart between the rooms. Accessing the stored logbook data on the glucometers revealed they were regularly used between the two individuals in less than one minute, insufficient time to allow adequate disinfection.
Routine HBV vaccination is recommended for individuals younger than 60 years of age, although vaccination of anyone at risk is always appropriate. The authors reasoned that diabetes should be considered a risk factor for bloodborne pathogen transmission, especially if an individual requires long-term care and routine assisted glucose monitoring.
Carol A. Kemper, MD, FIDSA, is Medical Director, Infection Prevention, El Camino Hospital, Palo Alto Medical Foundation.
Visceral Larva Migrans from Baylisascariasis; Measles Testing of Persons with HIV; Ambulatory Glucose Monitoring a Risk for Bloodborne Pathogens
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