A 2015 outbreak of flea-borne rickettsiosis in San Gabriel Valley, Los Angeles County, California.

Although flea-borne rickettsiosis is endemic in Los Angeles County, outbreaks are rare. In the spring of 2015 three human cases of flea-borne rickettsiosis among residents of a mobile home community (MHC) prompted an investigation. Fleas were ubiquitous in common areas due to presence of flea-infested opossums and overabundant outdoor cats and dogs. The MHC was summarily abated in June 2015, and within five months, flea control and removal of animals significantly reduced the flea population. Two additional epidemiologically-linked human cases of flea-borne rickettsiosis detected at the MHC were suspected to have occurred before control efforts began. Molecular testing of 106 individual and 85 pooled cat fleas, blood and ear tissue samples from three opossums and thirteen feral cats using PCR amplification and DNA sequencing detected rickettsial DNA in 18.8% of the fleas. Seventeen percent of these cat fleas tested positive for R. felis-specific DNA compared to under two (<2) percent for Candidatus R. senegalensis-specific DNA. In addition, serological testing of 13 cats using a group-specific IgG-ELISA detected antibodies against typhus group rickettsiae and spotted fever group rickettsiae in six (46.2%) and one (7.7%) cat, respectively. These results indicate that cats and their fleas may have played an active role in the epidemiology of the typhus group and/or spotted fever group rickettsial disease(s) in this outbreak.

Increase in Reports of Strongyloides Infection - Los Angeles County, 2013-2014.

During the 1990s, reports of infection with the nematode (roundworm) Strongyloides stercoralis submitted to the Los Angeles County Department of Public Health (LACDPH) ranged from 40 to 50 per year, but by 2000, reports had decreased to five per year; in 2006, Strongyloides infection was removed from the LACDPH reportable disease list. Currently, it is only reported at the discretion of Los Angeles County clinicians and laboratories as an unusual disease occurrence. LACDPH currently only monitors case counts and does not investigate reported Strongyloides cases. During 2013-2014, an increase in Strongyloides cases occurred, with 43 cases reported.

Challenges and opportunities in detecting Taenia solium tapeworm carriers in Los Angeles County California, 2009-2014.

Carriers of the pork tapeworm, Taenia solium, are the sole source of neurocysticercosis, a parasitic tissue infection that can be chronic and severe. Identifying T. solium tapeworm carriers is challenging. Many are asymptomatic and go undetected and unreported. In addition, T. solium is difficult to distinguish from other Taenia species of less concern. From 2009 to 2014, 24 taeniasis cases were reported to the Los Angeles County (LAC) Department of Public Health. Twenty reports were received solely from our automated electronic laboratory reporting system (ELR), two from health care providers, and two were generated internally from investigation of households with a reported neurocysticercosis case. Further investigation identified one T. solium carrier originally reported by ELR and one identified from a neurocysticercosis case investigation. These results suggest that T. solium tapeworm carriers can be identified from investigation of ELR reports of unspeciated Taenia cases as well as from households of neurocysticercosis cases.

Aseptic meningitis outbreak associated with echovirus 30 among high school football players--Los Angeles County, California, 2014.

On August 4, 2014, the Acute Communicable Disease Control Program of the Los Angeles County Department of Public Health received a report of three aseptic meningitis cases among football players at a county high school. An investigation was conducted to determine the extent of the outbreak, identify potential exposures, and recommend control measures. An outbreak-associated aseptic meningitis case was defined as an illness of any team or family member with onset during July 28-August 11 with 1) cerebrospinal fluid pleocytosis and negative bacterial culture or 2) an emergency department visit with headache, fever, and stiff neck. Ten cases were identified; nine in males, and one in a female; patient ages ranged from 13 to 17 years. All the patients sought care at an emergency department, and five were hospitalized, resulting in 12 total hospital days. All 10 patients have recovered. Eight patients were football players, and two were siblings of football players. The most affected subgroup was the junior varsity football team, with seven cases out of 57 players (attack rate = 12.3%); the relative risk for aseptic meningitis was higher among players who were linemen than among those who were not linemen (relative risk = 5.4 [p = 0.03]). Of the 10 patients, eight tested positive by polymerase chain reaction for enterovirus, and two were not tested. Echovirus testing was performed at the California Viral and Rickettsial Disease Laboratory. Of the eight specimens testing positive for enterovirus, seven tested positive for echovirus 30, and one specimen could not be typed because of insufficient quantity.

Notes from the field: identification of a Taenia tapeworm carrier - Los Angeles County, 2014.

Carriers of the pork tapeworm, Taenia solium, are the sole source of cysticercosis, a parasitic tissue infection. When tapeworm eggs excreted by the carrier are ingested, tapeworm larvae can form cysts. When cysts form in the brain, the condition is called neurocysticercosis and can be especially severe. In Los Angeles County an average of 136 county residents are hospitalized with neurocysticercosis each year. The prevalence of Taenia solium carriage is largely unknown because carriage is asymptomatic, making detection difficult. The identification and treatment of tapeworm carriers is an important public health measure that can prevent additional neurocysticercosis cases.

The impact of neurocysticercosis in california: a review of hospitalized cases.

To assess the burden of neurocysticercosis (NCC) in California we examined statewide hospital discharge data for 2009. There were 304 cases hospitalized with NCC identified (incidence = 0.8 per 100,000). Cases were mostly Latino (84.9%), slightly more likely to be male than female (men 57.6%, women 42.4%) with an average age of 43.5 years. A majority of cases were hospitalized in Southern California (72.1%) and many were hospitalized in Los Angeles County (44.7%). Men were more likely than women to have severe disease including hydrocephalus (29.7% vs. 18.6%, p = 0.027), resulting in longer hospitalizations (>4 days, 48.0% vs. 32.6%, p = 0.007) that were more costly (charge>$40 thousand men = 46.9% vs. woman = 4.1%, p = 0.026). Six deaths were recorded (2.0%). The total of NCC-related hospital charges exceeded $17 million; estimated hospital costs exceeded $5 million. Neurocysticercosis causes appreciable disease and exacts a considerable economic burden in California.

Strongyloidiasis-related deaths in the United States, 1991-2006.

The objective of this study was to 1) assess the incidence of strongyloidiasis in the United States, 2) evaluate demographic and regional associations, and 3) identify comorbid conditions as risk factors for death. A population-based case-control study was performed by using mortality data during 1991-2006. We identified 347 strongyloidiasis deaths (0.79 per 10 million deaths, 14-29 deaths per year), which decreased slightly over time. Deaths occurred primarily among older (median age = 66.0 years), white (57.6%) and Hispanic (22.2%) men (69.2%), residing in the Southeastern United States (49.3%). Associated health conditions included chronic obstructive pulmonary disease (28.7%, odds ratio [OR] = 4.0, 95% confidence interval [CI] = 3.0-5.4) and infection with human immunodeficiency virus (12.5%, OR = 4.6, 95% CI = 2.7-7.9). Strongyloidiasis deaths in the second half of the study period (1999-2006) were less likely to be associated with chronic obstructive pulmonary disease (19.4%, OR = 1.2, 95% CI = 0.7-1.9), but continued to be associated with human immunodeficiency virus infection (12.9%, OR = 2.8, 95% CI = 1.3-6.0). Early detection and treatment of at-risk patients with latent strongyloidiasis infections is needed to reduce strongyloidiasis mortality.

Use of statewide hospital discharge data to evaluate the economic burden of neurocysticercosis in Los Angeles County (1991-2008).

Statewide hospital discharge data were used to assess the economic burden of neurocysticercosis in Los Angeles County (LAC) from 1991 through 2008. A neurocysticercosis hospitalization was defined as having a discharge diagnosis of cysticercosis in addition to convulsions, seizures, hydrocephalus, cerebral edema or cerebral cysts. This study identified 3,937 neurocysticercosis hospitalizations, with the number of annual hospitalizations remaining relatively unchanged over the study period (R(2) = 0.01), averaging 219 per year (range 180-264). The total of all neurocysticercosis hospitalization charges over the study period was $136.2 million, averaging $7.9 million per year. The average charge per patient was $37.6 thousand and the most common payment method was Medicaid (43.9%), followed by private insurance (24.5%). The average length of stay was 7.2 days. The substantial number of hospitalizations and significant economic cost underscore the importance of neurocysticercosis in LAC.

West Nile virus infection in the pediatric population.

In 2004, Los Angeles County confirmed 11 cases of symptomatic West Nile virus (WNV) infections in children younger than 18 years of age. Eight had WNV fever, 2 had meningitis and 1 had encephalitis. Fever, rash, nausea and vomiting were the most prominent symptoms at presentation; median duration of illness was 7 days. Clinicians should be aware of the risk of WNV illness, confirm this diagnosis and report suspected WNV cases to their local health department.