Raoult Ratard

Primary Amebic Meningoencephalitis Deaths Associated With Sinus Irrigation Using Contaminated Tap Water

BACKGROUND Naegleria fowleri is a climate-sensitive, thermophilic ameba found in the environment, including warm, freshwater lakes and rivers. Primary amebic meningoencephalitis (PAM), which is almost universally fatal, occurs when N. fowleri-containing water enters the nose, typically during swimming, and N. fowleri migrates to the brain via the olfactory nerve. In 2011, 2 adults died in Louisiana hospitals of infectious meningoencephalitis after brief illnesses. METHODS Clinical and environmental testing and case investigations were initiated to determine the cause of death and to identify the exposures. RESULTS Both patients had diagnoses of PAM. Their only reported water exposures were tap water used for household activities, including regular sinus irrigation with neti pots. Water samples, tap swab samples, and neti pots were collected from both households and tested; N. fowleri were identified in water samples from both homes. CONCLUSIONS These are the first reported PAM cases in the United States associated with the presence of N. fowleri in household plumbing served by treated municipal water supplies and the first reports of PAM potentially associated with the use of a nasal irrigation device. These cases occurred in the context of an expanding geographic range for PAM beyond southern tier states with recent case reports from Minnesota, Kansas, and Virginia. These infections introduce an additional consideration for physicians recommending nasal irrigation and demonstrate the importance of using appropriate water (distilled, boiled, filtered) for nasal irrigation. Furthermore, the changing epidemiology of PAM highlights the importance of raising awareness about this disease among physicians treating persons showing meningitislike symptoms.

Chronic Disease and Related Conditions at Emergency Treatment Facilities in the New Orleans Area After Hurricane Katrina

BACKGROUND Disaster preparations usually focus on preventing injury and infectious disease. However, people with chronic disease and related conditions (CDRCs), including obstetric/gynecological conditions, may be vulnerable to disruptions caused by disasters. METHODS We used surveillance data collected after Hurricane Katrina to characterize the burden of visits for CDRCs at emergency treatment facilities (eg, hospitals, disaster medical assistance teams, military aid stations). In 6 parishes in and around New Orleans, health care providers at 29 emergency treatment facilities completed a standardized questionnaire for injury and illness surveillance from September 8 through October 22, 2005. RESULTS Of 21,673 health care visits, 58.0% were for illness (24.3% CDRCs, 75.7% non-CDRCs), 29.1% for injury, 7.2% for medication refills, and 5.7% for routine or follow-up care. The proportion of visits for CDRCs increased with age. Among men presenting with CDRCs, the most common illnesses were cardiovascular disease (36.8%), chronic lower-respiratory disease (12.3%), and diabetes/glucose abnormalities (7.7%). Among women presenting with CDRCs, the most common were cardiovascular disease (29.2%), obstetric/gynecological conditions (18.2%), and chronic lower-respiratory disease (12.0%). Subsequent hospitalization occurred among 28.7% of people presenting with CDRCs versus 10.9% of those with non-CDRCs and 3.8% of those with injury. CONCLUSIONS Our data illustrate the importance of including CDRCs as a part of emergency response planning.

The First Association of a Primary Amebic Meningoencephalitis Death With Culturable Naegleria fowleri in Tap Water From a US Treated Public Drinking Water System

BACKGROUND Naegleria fowleri is a climate-sensitive, thermophilic ameba found in warm, freshwater lakes and rivers. Primary amebic meningoencephalitis (PAM), which is almost universally fatal, occurs when N. fowleri-containing water enters the nose, typically during swimming, and migrates to the brain via the olfactory nerve. In August 2013, a 4-year-old boy died of meningoencephalitis of unknown etiology in a Louisiana hospital. METHODS Clinical and environmental testing and a case investigation were initiated to determine the cause of death and to identify potential exposures. RESULTS Based on testing of cerebrospinal fluid and brain specimens, the child was diagnosed with PAM. His only reported water exposure was tap water; in particular, tap water that was used to supply water to a lawn water slide on which the child had played extensively prior to becoming ill. Water samples were collected from both the home and the water distribution system that supplied the home and tested; N. fowleri was identified in water samples from both the home and the water distribution system. CONCLUSIONS This case is the first reported PAM death associated with culturable N. fowleri in tap water from a US treated drinking water system. This case occurred in the context of an expanding geographic range for PAM beyond southern states, with recent case reports from Minnesota, Kansas, and Indiana. This case also highlights the role of adequate disinfection throughout drinking water distribution systems and the importance of maintaining vigilance when operating drinking water systems using source waters with elevated temperatures.

Prevalence of community-associated methicillin-resistant Staphylococcus aureus colonization outside the healthcare environment

Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections are increasingly recognized in persons without established risk factors. Population-based prevalence studies of CA-MRSA colonization in persons without risk factors are relatively limited. Subjects aged 2-65 years were enrolled from a student recreation centre, public office building, and out-patient clinics. Persons or close contacts with a history of hospitalization, nursing-home residence, surgery, emergency-department visit, or healthcare employment during the previous year and persons with chronic debilitating illness, indwelling catheter, or surgical device were excluded. Swabs of anterior nares were obtained. Demographic and clinical information was collected. During January-June 2005, three (1.2%) of 259 subjects were colonized with MRSA. All three subjects were adults enrolled at the recreation centre. Healthy persons living in households without recent exposure to healthcare environments were at low risk for MRSA colonization. Studies from other geographic locations are needed to elucidate differences in prevalence of CA-MRSA.

Outbreak of Francisella novicida Bacteremia Among Inmates at a Louisiana Correctional Facility

BACKGROUND Francisella novicida is a rare cause of human illness despite its close genetic relationship to Francisella tularensis, the agent of tularemia. During April-July 2011, 3 inmates at a Louisiana correctional facility developed F. novicida bacteremia; 1 inmate died acutely. METHODS We interviewed surviving inmates; reviewed laboratory, medical, and housing records; and conducted an environmental investigation. Clinical and environmental samples were tested by culture, real-time polymerase chain reaction (PCR), and multigene sequencing. Isolates were typed by pulsed-field gel electrophoresis (PFGE). RESULTS Clinical isolates were identified as F. novicida based on sequence analyses of the 16S ribosomal RNA, pgm, and pdpD genes. PmeI PFGE patterns for the clinical isolates were indistinguishable. Source patients were aged 40-56 years, male, and African American, and all were immunocompromised. Two patients presented with signs of bacterial peritonitis; the third had pyomyositis of the thigh. The 3 inmates had no contact with one another; their only shared exposures were consumption of municipal water and of ice that was mass-produced at the prison in an unenclosed building. Swabs from one set of ice machines and associated ice scoops yielded evidence of F. novicida by PCR and sequencing. All other environmental specimens tested negative. CONCLUSIONS To our knowledge, this is the first reported common-source outbreak of F. novicida infections in humans. Epidemiological and laboratory evidence implicate contaminated ice as the likely vehicle of transmission; liver disease may be a predisposing factor. Clinicians, laboratorians, and public health officials should be aware of the potential for misidentification of F. novicida as F. tularensis.

Vibrio vulnificus Bacteremia Associated with Chronic Lymphocytic Leukemia, Hypogammaglobulinemia, and Hepatic Cirrhosis: Relation to Host and Exposure Factors in 252 V. Vulnificus Infections Reported in Louisiana

Background: Vibrio vulnificus infection in persons with B-chronic lymphocytic leukemia (B-CLL) or hypogammaglobulinemia has been reported infrequently. Patient and Methods: A woman with B-CLL, hypogammaglobulinemia, and hepatic cirrhosis died of V. vulnificus bacteremia after eating cooked shrimp and crabs. We reviewed host and exposure data in 252 cases of V. vulnificus infection reported in Louisiana during the interval of 1980 through 2004. Results: V. vulnificus was isolated from blood in 122 cases (48.8%). Preexisting conditions in 138 cases included liver disease (41.3%), malignancy (13.8%), and immunosuppression (9.4%). The prevalence of preexisting conditions was significantly greater in cases with positive blood cultures than in cases with positive wound or stool cultures. Exposure data in 116 cases revealed crab consumption without raw oyster consumption or seawater exposure in 3.4%. Conclusion: The present patient had several conditions associated with increased risk of V. vulnificus infection and bacteremia, especially hepatic cirrhosis, but her route of exposure to V. vulnificus was unusual.

Epidemiology of animal rabies and its practical application to pre- and postexposure prophylaxis, louisiana, 1988 to 2007.

The incidence of human rabies in the United States has decreased significantly over the past century. This analysis examines the ecological status of rabies in Louisiana with the intent of identifying differences in risk of rabies transmission from exposures to different species of animals. Louisiana presently harbors one terrestrial variant of rabies, a skunk variant, and several bat variants. Surveillance data collected from 1988 through 2007 were examined, comparing areas of the state characterized by circulating terrestrial variants and areas free of terrestrial rabies. Nine state public health regions were also compared. The proportions of rabies-positive laboratory submissions from each species and/or species group were used as indicators of risk. In addition, differences in proportions positive were examined temporally. A significant proportion of positive bats (9.64%) and skunks (44.3%), examined after biting or otherwise exposing a human being, were identified by diagnostic laboratories. Samples from wild terrestrial animals originating in areas known to harbor circulating terrestrial rabies variants were more than 30 times more likely to be positive for rabies than samples originating from areas thought to be free of terrestrial rabies. Bats were also slightly more likely to be positive when submitted from areas known to be endemic for terrestrial rabies. Rabies in pets and agricultural animals were rarely reported. Seasonal variations in prevalence of positive tests were also identified. The results of this examination of rabies epidemiology in Louisiana can be used in determining recommendations for both pre- and postexposure rabies prophylaxis. Similar applications of surveillance data are encouraged in other jurisdictions.

Infectious Disease Epidemiology

The following chapter intends to give the reader an overview of the current field of applied infectious disease epidemiology. Prevention of disease by breaking the chain of transmission has traditionally been the main purpose of infectious disease epidemiology. While this goal remains the same, the picture of infectious diseases is changing. New pathogens are identified and already known disease agents are changing their behavior. The world population is aging; more people develop underlying disease conditions and are therefore more susceptible to certain infectious diseases or have long term sequelae after being infected.