Human exposure to rabid free-ranging cats: a continuing public health concern in Pennsylvania.

Rabid free-ranging cats have been a public health concern in Pennsylvania since raccoon variant rabies first was recognized in the state in the early 1980s. Over the last decade, between 1.5 and 2.5% of cats submitted to Pennsylvania's state laboratories for rabies testing have been positive. In this report, we describe the extent of rabies in free-ranging cats in Pennsylvania. We also present two examples of human exposure to rabid free-ranging cats that occurred in Pennsylvania during 2010-2011 and the public health actions taken to address rabies exposure in the humans and animals. We then describe the concerns surrounding the unvaccinated and free-ranging cat population in Pennsylvania and possible options in managing this public and animal health problem.

Yersinia enterocolitica infections associated with improperly pasteurized milk products: southwest Pennsylvania, March-August, 2011.

In July 2011, a cluster of Yersinia enterocolitica infections was detected in southwestern Pennsylvania, USA. We investigated the outbreak's source and scope in order to prevent further transmission. Twenty-two persons were diagnosed with yersiniosis; 16 of whom reported consuming pasteurized dairy products from dairy A. Pasteurized milk and food samples were collected from this dairy. Y. enterocolitica was isolated from two products. Isolates from both food samples and available clinical isolates from nine dairy A consumers were indistinguishable by pulsed-field gel electrophoresis. Environmental and microbiological investigations were performed at dairy A and pasteurization deficiencies were noted. Because consumption of pasteurized milk is common and outbreaks have the potential to become large, public health interventions such as consumer advisories or closure of the dairy must be implemented quickly to prevent additional cases if epidemiological or laboratory evidence implicates pasteurized milk as the outbreak source.

Concurrent 2009 pandemic influenza A (H1N1) virus infection in ferrets and in a community in Pennsylvania.

We report a fall 2010 cluster of pandemic influenza A/H1N1 (pH1N1) infections in pet ferrets in Lehigh Valley region of Pennsylvania. The ferrets were associated with one pet shop. The influenza cluster occurred during a period when the existing human surveillance systems had identified little to no pH1N1 in humans in the Lehigh Valley, and there were no routine influenza surveillance systems for exotic pets. The index case was a 2.5-month-old neutered male ferret that was presented to a veterinary clinic with severe influenza-like illness (ILI). In response to laboratory notification of a positive influenza test result, and upon request from the Pennsylvania Department of Health (PADOH), the Pennsylvania Department of Agriculture (PDA) conducted an investigation to identify other ill ferrets and to identify the source and extent of infection. PDA notified the PADOH of the pH1N1 infection in the ferrets, leading to enhanced human surveillance and the detection of pH1N1 human infections in the surrounding community. Five additional ferrets with ILI linked to the pet shop were identified. This simultaneous outbreak of ferret and human pH1N1 demonstrates the important link between animal health and public health and highlights the potential use of veterinary clinics for sentinel surveillance of diseases shared between animals and humans.

Fatal pandemic (H1N1) 2009 influenza A virus infection in a Pennsylvania domestic cat.

We report the earliest recognized fatality associated with laboratory-confirmed pandemic H1N1 (pH1N1) influenza in a domestic cat in the United States. The 12-year old, indoor cat died on 6 November 2009 after exposure to multiple family members who had been ill with influenza-like illness during the peak period of the fall wave of pH1N1 in Pennsylvania during late October 2009. The clinical presentation, history, radiographic, laboratory and necropsy findings are presented to assist veterinary care providers in understanding the features of this disease in cats and the potential for transmission of infection to pets from infected humans.

The Epidemic Intelligence Service in the United States.

The Epidemic Intelligence Service (EIS) - the two year applied epidemiology training programme of the United States (US) Centers for Disease Control and Prevention (CDC) - celebrates its 50th anniversary in 2001. Developed during the Korean war, only five years after CDC was established, the stimulus behind developing the EIS was a lack of trained field investigators should biological agents be intentionally used against the US population. It was, however, clear to Alexander Langmuir, the head of epidemiology at CDC and founder of the EIS, that his trainees would engage in a wide range of activities and help fill gaps in the US for epidemiologists with the skills and practical field experience to investigate and control naturally occurring outbreaks of diseases.

Biological warfare training. Infectious disease outbreak differentiation criteria.

The threat of biological terrorism and warfare may increase as the availability of weaponizable agents increase, the relative production costs of these agents decrease, and, most importantly, there exist terrorist groups willing to use them. Therefore, an important consideration during the current emphasis of heightened surveillance for emerging infectious diseases is the capability to differentiate between natural and intentional outbreaks. Certain attributes of a disease outbreak, while perhaps not pathognomic for a biological attack when considered singly, may in combination with other attributes provide convincing evidence for intentional causation. These potentially differentiating criteria include proportion of combatants at risk, temporal patterns of illness onset, number of cases, clinical presentation, strain/variant, economic impact, geographic location, morbidity/mortality, antimicrobial resistance patterns, seasonal distribution, zoonotic potential, residual infectivity/toxicity, prevention/therapeutic potential, route of exposure, weather/climate conditions, incubation period, and concurrence with belligerent activities of potential adversaries.

Incidence and clinical implications of isolation of Mycobacterium kansasii: results of a 5-year, population-based study.

BACKGROUND: Mycobacterium kansasii, an unusual pathogen in the pre-AIDS era, is increasingly reported to cause infection among patients with HIV infection. Little is known about the epidemiology and clinical implications of M. kansasii infection in the AIDS era. OBJECTIVE: To compare the incidence, demographic characteristics, and clinical features of M. kansasii infection in HIV-positive and HIV-negative persons. DESIGN: Population-based laboratory surveillance. SETTING: Three counties in northern California. PATIENTS: All persons who had a positive culture for M. kansasii between 1 January 1992 and 31 December 1996. MEASUREMENTS: Cumulative incidence rates were calculated for each year by dividing the number of adult patients by the annual estimated adult population. Demographic and socioeconomic data for a single county were obtained by linkage with the 1990 U.S. Census report. RESULTS: 270 patients (69.3% of whom were HIV positive) were identified, for an incidence of 2.4 cases per 100,000 adults per year (95% CI, 2.1 to 2.7), 115 cases per 100,000 HIV-positive persons per year (CI, 99 to 133), and 647 cases per 100,000 persons with AIDS per year (CI, 554 to 751). Indicators of lower socioeconomic status were common among patients: Median incomes were $32,317 in census tracts in which cases were identified and $38,048 in census tracts without cases (P = 0.001), and 35.7% of patients had unstable housing situations. Ninety-four percent of cases were from respiratory isolates, and 87.5% of patients had evidence of infection. Persons with HIV infection differed from those without HIV infection with respect to mycobacteremia (9.6% compared with 0%; P = 0.001), need for hospitalization (77.4% compared with 51.9%; P < 0.001), and smear positivity (41.7% compared with 20.7%; P = 0.005). Chronic diseases were common among HIV-negative persons; however, 40.3% had no predisposing medical condition. CONCLUSIONS: Mycobacterium kansasii isolation is more common in HIV-positive persons, but most patients with M. kansasii infection have clinical and radiologic evidence of infection regardless of HIV status. Persons infected with HIV and M. kansasii have a higher rate of hospitalization and a greater burden of organisms. A possible association with poverty suggests mechanisms of transmission and requires further study.

Biological warfare training: infectious disease outbreak differentiation criteria.

The threat of biological terrorism and warfare may increase as the availability of weaponizable agents increases, the relative production costs of these agents decrease, and, most importantly, there exist terrorist groups willing to use them. Therefore, an important consideration during the current period of heightened surveillance for emerging infectious diseases is the ability to differentiate between natural and intentional outbreaks. Certain attributes of a disease outbreak, although perhaps not pathognomonic for a biological attack when considered singly, may combine to provide convincing evidence of intentional causation. These potentially differentiating criteria include proportion of combatants at risk, temporal patterns of illness onset, number of cases, clinical presentation, strain/variant, economic impact, geographic location, morbidity/mortality, antimicrobial resistance patterns, seasonal distribution, zoonotic potential, residual infectivity/toxicity, prevention/therapeutic potential, route of exposure, weather/climate conditions, incubation period, and concurrence with belligerent activities of potential adversaries.

Emerging infectious diseases and travel medicine.

International movement of individuals, populations, and products is one of the major factors associated with the emergence and reemergence of infectious diseases as the pace of global travel and commerce increases rapidly. Travel can be associated with disease emergence because (1) the disease arises in an area of heavy tourism, (2) tourists may be at heightened risk because of their activities, or (3) because they can act as vectors to transport the agent to new areas. Examples of recently recognized diseases with relationship to travel include HIV, Legionnaire's disease, cyclosporiasis, Vibrio cholerae O139 Bengal, hantavirus, and variant Creutzfeldt-Jacob disease. Reemerging diseases include dengue fever, malaria, cholera, schistosomiasis, leptospirosis, and viral hemorrhagic fevers. In addition, tuberculosis, drug-resistant shigellosis, and cholera have been major concerns in refugee and migrant populations. Because of the unique role of travel in emerging infections, efforts are underway to address this factor by agencies such as the CDC, WHO, the International Society of Travel Medicine, and the travel industry.

Perspectives in fatal epidemics.

This article discusses four epidemics of fatal infectious diseases: a 1993 cluster of deaths among previously healthy persons in the southwestern United States that led to the identification of a new clinical syndrome, hantavirus pulmonary syndrome; the first epidemic of Ebola hemorrhagic fever identified in nearly two decades occurring in 1995 in Zaire, which resulted in 317 cases with a mortality rate of 77%; an outbreak of Legionnaires' disease among cruise ship passengers in 1994; and a 1989 cluster of illnesses among nonhuman primates in Reston, Virginia leading to the identification of a new strain of Ebola virus. In each outbreak, the public health emergency was recognized and reported by alert clinicians, and the control of disease was facilitated through rapid, coordinated responses involving multiple agencies. Such collaboration between clinical and public health entities and among various agencies will be increasingly needed as surveillance and diagnostic capabilities for emerging and reemerging infectious diseases are enhanced around the world.

Resistance patterns of Streptococcus pneumoniae and Haemophilus influenzae isolates recovered in Egypt from children with pneumonia. The Antimicrobial Resistance Surveillance Study Group.

Treatment of childhood pneumonia in developing countries requires knowledge of susceptibility patterns for Streptococcus pneumoniae and Haemophilus influenzae. Between October 1991 and April 1993, a surveillance survey of antimicrobial resistance was performed at two fever hospitals in Egypt; nasopharyngeal swab and blood specimens obtained from 1,635 children with pneumonia were cultured for these organisms. Susceptibility testing of these organisms was performed. At least one of these organisms was isolated from nasopharyngeal swab specimens from 73% of the children; 3.7% of blood cultures were positive. For S. pneumoniae strains, 70.9% of nasopharyngeal isolates were calculated to be susceptible to penicillin vs. 77.6% of blood isolates; the percentages of isolates susceptible to co-trimoxazole were 73.0% and 75.0%, respectively. For H. influenzae strains, 93.0% of nasopharyngeal isolates were calculated to be susceptible to ampicillin vs. 100% of blood isolates; the percentages of isolates susceptible to co-trimoxazole were 84.9% and 100%, respectively. Although most S. pneumoniae and H. influenzae strains associated with childhood pneumonia in Cairo were susceptible to penicillins and co-trimoxazole, antimicrobial resistance did not occur.

Emerging infectious diseases in the institutional setting: another hot zone.

During the closing years of the 20th century, there has been an unprecedented number of newly recognized infectious agents and a resurgence of infectious diseases only recently thought to be conquered. These problems have been compounded by the increasing number of pathogens that have evolved resistance to antimicrobial agents. Hospitals and other institutional settings occupy a pivotal niche in the emergence of infectious agents due to factors such as the large concentrations of ill and immuno-compromised persons, evolving technologies in healthcare settings, routine breeches of host defense mechanisms, and frequent use of antimicrobial agents. Any comprehensive strategy to address emerging infectious diseases must incorporate provisions for healthcare settings, including efforts to enhance surveillance, response capacity, training, education, applied research, and routine implementation of prevention measures.

Monovalent latex agglutination reagents for the diagnosis of nonmeningitic pneumococcal infection.

The pneumococcus is a leading cause of serious bacterial infection worldwide. Given the difficulties with available assays for the diagnosis of invasive nonmeningitic pneumococcal infection, we evaluated monovalent slide latex agglutination reagents among patients with blood culture-confirmed pneumococcal infection and control patients in Baltimore, Maryland, USA; São Paulo, Brazil; and Cairo, Egypt. Among 50 patients with invasive nonmeningitic pneumococcal infection, 23 had a positive urine test for a sensitivity of 46% (95% confidence intervals of 32% and 61%). Among 39 healthy children, 36 had a negative assay, for a specificity of 92% (95% confidence intervals of 78% and 98%). Among 80 children with pneumonia without a positive blood culture for Streptococcus pneumoniae, the specificity was 88% (95% confidence intervals of 78% and 94%). Although the assay was fairly specific, the positive predictive value using optimistic assumptions was only 73%-83%. This study suggests that this assay has a sensitivity and positive predictive value that may limit its value in some settings.

Preventing disseminated Mycobacterium avium complex disease in patients infected with human immunodeficiency virus.

Disseminated Mycobacterium avium complex (MAC) infection is an important late-stage complication of infection with the human immunodeficiency virus. Since MAC is widely dispersed in the environment, the source of infection for patients with disseminated MAC generally cannot be determined. Therefore, specific recommendations for avoiding exposure are not supported at this time. Routine screening of stools and sputum to detect MAC colonization as a means of targeting prophylaxis for disseminated disease is also not recommended at present. Two randomized, placebo-controlled trials have demonstrated that prophylactic use of rifabutin in persons with low CD4 lymphocyte counts results in a 50% decrease in MAC bacteremia as well as a reduction in some signs, symptoms, and laboratory abnormalities associated with MAC disease. Thus a prophylactic daily dose of rifabutin (300 mg) should be considered for adults who have had a previous AIDS-defining opportunistic illness and who have a CD4 lymphocyte count of < 75/microL. Many experts would consider prophylaxis appropriate only when the CD4 lymphocyte count is < 50/microL, particularly when there has not been a previous AIDS-defining opportunistic infection. Clinicians should be aware of drug interactions and potential adverse effects associated with the use of rifabutin. Preliminary reports of randomized, placebo-controlled trials suggest that chemoprophylaxis with clarithromycin is also effective in the prevention of disseminated MAC disease, and evaluation of other agents is under way. Prophylaxis for disseminated MAC infection in children has not been evaluated but is presumed to be as effective as that in adults. Decisions regarding initiation of MAC chemoprophylaxis should be individualized.

Mycobacterium avium complex in water, food, and soil samples collected from the environment of HIV-infected individuals.

As part of an epidemiologic study of Mycobacterium avium complex (MAC) infection in San Francisco, water, food and soil samples were collected from the home environment of 290 persons with human immunodeficiency virus (HIV) infection and cultured for mycobacteria. Isolates recovered from the environment were compared with isolates cultured from study patients. Although mycobacteria were recovered from numerous environmental samples, isolates reactive with MAC-specific DNA probes were recovered from only four of 528 (0.76%) water samples and one of 397 (0.25%) food samples. The species M. avium was recovered from one water (0.19%) and one food sample. In contrast, MAC was recovered from 55% and M. avium from 27% of soil samples taken from potted plants in patients' home. Speciation of 76 MAC isolates from study patients showed all isolates belonged to the species M. avium. With use of serotype and multilocus enzyme electrophoresis analysis, some of the soil isolates were found to be similar to isolates recovered from study patients. The results of this study suggest that soil, rather than water, may be a significant reservoir of organisms causing MAC infection in San Francisco.

Transmission of multidrug-resistant Mycobacterium tuberculosis among persons exposed in a medical examiner's office, New York.

OBJECTIVE: To determine the prevalence of and risk factors for having a positive tuberculin skin test (TST) result among employees at a medical examiner's office (MEO). DESIGN: Cohort study, environmental investigation. SETTING: Several employees at a medical examiner's office were found to have positive TST results after autopsies were performed on persons with multidrug-resistant tuberculosis (MDR-TB). PARTICIPANTS: Employees of the MEO. RESULTS: Of 18 MEO employees, 5 (28%) had a positive TST result; 2 of these 5 had TST conversions. We observed a trend between TST conversion and participation in autopsies on persons with MDR-TB (2 of 2 converters versus 3 of 13 employees with negative TST; relative risk = 4.3; 95% confidence interval 1.61 to 11.69; P = 0.10). The environmental investigation revealed that the autopsy room was at positive pressure relative to the rest of the MEO and that air from the autopsy room mixed throughout the facility. CONCLUSIONS: A systematic approach to preventing transmission of Mycobacterium tuberculosis in autopsy suites should include effective environmental controls and routine tuberculin skin testing of employees.