Learning and memory difficulties after environmental exposure to waterways containing toxin-producing Pfiesteria or Pfiesteria-like dinoflagellates.

BACKGROUND: At the beginning of autumn, 1996, fish with "punched-out" skin lesions and erratic behaviour associated with exposure to toxins produced by Pfiesteria piscicida or Pfiesteria-like dinoflagellate species were seen in the Pocomoke River and adjacent waterways on the eastern shore of the Chesapeake Bay in Maryland, USA. In August, 1997, fish kills associated with Pfiesteria occurred in these same areas. People who had had contact with affected waterways reported symptoms, including memory difficulties, which raises questions about the human-health impact of environmental exposure to Pfiesteria toxins. METHODS: We assessed 24 people who had been exposed. We collected data on exposure history and symptoms, did a complete medical and laboratory assessment (13 people), and carried out a neuropsychological screening battery. Performance on neuropsychological measures was compared with a matched control group. RESULTS: People with high exposure were significantly more likely than occupationally matched controls to complain of neuropsychological symptoms (including new or increased forgetfulness); headache; and skin lesions or a burning sensation of skin on contact with water. No consistent physical or laboratory abnormalities were found. However, exposed people had significantly reduced scores on the Rey Auditory Verbal Learning and Stroop Color-Word tests (indicative of difficulties with learning and higher cognitive function), and the Grooved Pegboard task. There was a dose-response effect with the lowest scores among people with the highest exposure. By 3-6 months after cessation of exposure, all those assessed had test scores that had returned to within normal ranges. INTERPRETATION: People with environmental exposure to waterways in which Pfiesteria toxins are present are at risk of developing a reversible clinical syndrome characterised by difficulties with learning and higher cognitive functions. Risk of illness is directly related to degree of exposure, with the most prominent symptoms and signs occurring among people with chronic daily exposure to affected waterways.

Toxic-Pfiesteria--surveillance for human disease in Maryland.

The presence of toxic stages of the dinoflagellate Pfiesteria piscicida and other morphologically related organisms was documented in three estuarine waterways on the lower Eastern Shore of Maryland in 1997. The Maryland Department of Health and Mental Hygiene, working closely with the local health departments, established a surveillance system to collect reports of human illnesses. Maryland's experience has formed the base on which national surveillance criteria for Estuary Associated Syndrome have been developed and regional surveillance protocols have been built. The cooperation of practicing physicians is essential to continued surveillance efforts to further delineate the extent and nature of human health effects following exposures to waters where toxic forms of these dinoflagellates are active. Physicians wishing to report persons who may have Estuary Associated Syndrome should contact their local health department. Persons wanting information or wishing to report finding lesioned fish or a fish kill in progress should call the Maryland Pfiesteria Hotline at 1- 888-584-3110.

Toxic Pfiesteria and human health.

Toxic activity of a Pfiesteria-like organism occurred for much of 1997 in the waters of the lower Pocomoke River on Maryland's Eastern Shore. Maryland's experience with these toxic blooms of dinoflagellates, current knowledge of their potential human health effects, and the actions taken by state government agencies in response to a potential public health threat are reviewed. A medical diagnostic team commissioned by the Department of Health and Mental Hygiene evaluated a group of persons with intense exposures to lesioned fish or the waters from which they came and/or prominent symptoms following exposure to affected waters or lesioned fish. The principal findings of the team included consistent complaints of memory problems, acute burning of the skin following direct contact with water, and respiratory irritation. Findings on examination were limited to neurocognitive deficits in short-term memory and learning difficulties. Physicians and citizens are asked to continue to report, through their local health departments, illnesses thought to be related to exposure to lesioned fish or the waters from which they are taken. Persons with questions or wishing to report finding lesioned fish should call the state Pfiesteria hotline at 1-888-584-3110.

Case characteristics and trends in pediatric tuberculosis, Maryland, 1986-1993.

OBJECTIVE: To identify case characteristics and trends in the incidence of pediatric tuberculosis (TB) in Maryland during the national resurgence of the disease. METHODS: The authors conducted a retrospective review of the 248 cases of TB in children ages 19 and younger reported to the state registry between 1986 and 1993. RESULTS: The incidence of pediatric TB in Maryland, while showing a downward trend between 1986 and 1993, was characterized by a bimodal pattern, with one peak in children younger than age 5 and another peak in adolescents. Certain case characteristics differed significantly according to age: adolescents with TB were more likely to have positive AFB smears, positive cultures, and cavitary X-rays than children in the 0-4 age group. On the other hand, PPD results did not differ significantly by age. Children with TB came from households in zip code areas for which the median family income was lower and the rate of unemployment was higher than comparable statewide figures. CONCLUSIONS: Study findings indicate that (a) the general decline in adult TB in Maryland was accompanied by a decline among children; (b) age-specific case characteristics continue to be useful in clinical decision making for children with suspected TB; and (c) a state TB registry may prove useful not only in tracking disease trends and monitoring statewide control efforts but also in confirming case characteristics, all of which are important disease control issues in a time of fiscal downsizing.

Tuberculosis: optimism, pessimism, frustration.

The re-emergence of tuberculosis as a serious public health threat has captured the nation's attention. Tuberculosis more frequently affects the ethnic minorities and the socially and economically disadvantaged residents of Maryland. Effective regimens are available to treat and prevent tuberculosis. Consistent application of proven infection control measures and of treatment and prevention regimens will prevent the development and spread of multidrug-resistant tuberculosis.

Preventive therapy for tuberculosis in Maryland.

Maryland data substantiate the safety of isoniazid therapy in preventing tuberculosis. To eradicate tuberculosis in the U.S., private physicians must play an active role by offering preventive therapy to patients at high risk of developing the disease.

HIV antibody seroprevalence among childbearing women surveyed in Maryland.

Because blood specimens from newborns reflect the antibody status of the mother, seroprevalence rates among childbearing women are obtainable from analysis of the specimens. A blinded survey of human immunodeficiency virus (HIV) antibody seroprevalence among childbearing women was conducted in Maryland. The survey used 31,273 dried filter paper blood spot specimens obtained from newborns screened for hereditary disorders. Overall, 99 specimens were positive on two enzyme-linked immunoassays and on Western blot, providing a seroprevalence rate of 0.32 percent. The rate for child-bearing women residing within the City of Baltimore, 0.7 percent, was significantly higher than the rate for those residing elsewhere in Maryland, 0.1 percent. The statewide rate for nonwhite women, 0.8 percent, was higher than for white women, 0.007 percent. No statistically significant associations were found with residence in an inner city area, as opposed to residence in other areas of the city; birth weight group; reported health of the infant; or the infant having received a transfusion.

Prevalence of risk behaviors and HIV infection in Maryland STD clinics.

Persons who are receiving evaluation and treatment for sexually transmitted diseases are at moderately increased risk for acquiring HIV infections. The scope of STD clinic services should be broadened to include counseling, education, and referral services for health needs related to risk of HIV infection.

Human immunodeficiency virus infection among patients attending clinics for sexually transmitted diseases.

To assess the prevalence and associated risk factors for human immunodeficiency virus (HIV) infection in patients attending inner-city clinics for sexually transmitted diseases in Baltimore, we screened 4028 patients anonymously, of whom 209 (5.2 percent) were seropositive for HIV. HIV-seropositivity rates were higher among men (6.3 percent) than women (3.0 percent) (P less than 0.001) and among blacks (5.0 percent) than whites (1.2 percent) (P less than 0.02). Among men, but not women, HIV seroprevalence increased markedly and steadily up to the age of 40. In men, HIV seropositivity was independently associated with increased age, black race, a history of homosexual contact, and the use of parenteral drugs. In women, a history of parenteral drug use or of being a sexual partner of a bisexual man or parenteral drug user were independently predictive of HIV seropositivity. In men, HIV seropositivity was also associated with a history of syphilis or a reactive serologic test for syphilis, and in women, with a history of genital warts. Since these associations were independent of the type and number of reported sexual partners, they raise the possibility that sexually transmitted diseases that disrupt epithelial surfaces may be important in the transmissibility of HIV. In addition, on a self-administered questionnaire, one third of HIV-infected men and one half of infected women did not acknowledge previous high-risk behavior for HIV exposure. These data suggest that patients at clinics for sexually transmitted diseases represent a group at high risk for HIV infection, and that screening, counseling, and intensive education should be offered to all patients attending such clinics.