Maryam B. Haddad

Acute Flaccid Paralysis and West Nile Virus Infection

Acute weakness associated with West Nile virus (WNV) infection has previously been attributed to a peripheral demyelinating process (Guillain-Barré syndrome); however, the exact etiology of this acute flaccid paralysis has not been systematically assessed. To thoroughly describe the clinical, laboratory, and electrodiagnostic features of this paralysis syndrome, we evaluated acute flaccid paralysis that developed in seven patients in the setting of acute WNV infection, consecutively identified in four hospitals in St. Tammany Parish and New Orleans, Louisiana, and Jackson, Mississippi. All patients had acute onset of asymmetric weakness and areflexia but no sensory abnormalities. Clinical and electrodiagnostic data suggested the involvement of spinal anterior horn cells, resulting in a poliomyelitis-like syndrome. In areas in which transmission is occurring, WNV infection should be considered in patients with acute flaccid paralysis. Recognition that such weakness may be of spinal origin may prevent inappropriate treatment and diagnostic testing.

Vaccine effectiveness during a varicella outbreak among schoolchildren : Utah, 2002-2003

Objectives. In the context of a chickenpox outbreak involving 2 Utah elementary schools, we conducted an investigation to assess vaccine effectiveness, describe illness severity, and examine risk factors for breakthrough varicella (ie, varicella in those who have been vaccinated). Methods. All parents were asked to complete a questionnaire about their child’s medical history. Parents of children with recent varicella were interviewed, and vaccination records were verified. Lesions were submitted for polymerase chain reaction testing. Results. Questionnaires were returned for 558 (93%) of 597 students in school A and 924 (97%) of 952 students in school B. A total of 83 schoolchildren (57 unvaccinated and 26 vaccinated) had varicella during the October 2002 through February 2003 outbreak period. An additional 17 cases occurred among household contacts, including infants and adults. Polymerase chain reaction analysis recovered wild-type varicella. Vaccine effectiveness was 87%. With 1 notable exception, vaccinated children tended to have milder illness. Risk factors for breakthrough varicella included eczema, vaccination ≥5 years before the outbreak, and vaccination at ≤18 months of age. Restricting analysis to children vaccinated ≥5 years before the outbreak, those vaccinated at ≤18 months of age were more likely to develop breakthrough varicella (relative risk: 9.3; 95% confidence interval: 1.3–68.9). Conclusions. The vaccine, administered by >100 health care providers to 571 children during a 7-year time period, was effective. Risk factors for breakthrough varicella suggest some degree of biological interaction between age at vaccination and time since vaccination.

Coccidioidomycosis among workers at an archeological site, northeastern Utah.

In 2001, an outbreak of acute respiratory disease occurred among persons working at a Native American archeological site at Dinosaur National Monument in northeastern Utah. Epidemiologic and environmental investigations were undertaken to determine the cause of the outbreak. A clinical case was defined by the presence of at least two of the following symptoms: self-reported fever, shortness of breath, or cough. Ten workers met the clinical case definition; 9 had serologic confirmation of coccidioidomycosis, and 8 were hospitalized. All 10 were present during sifting of dirt through screens on June 19; symptoms began 9–12 days later (median 10). Coccidioidomycosis also developed in a worker at the site in September 2001. A serosurvey among 40 other Dinosaur National Monument workers did not find serologic evidence of recent infection. This outbreak documents a new endemic focus of coccidioidomycosis, extending northward its known geographic distribution in Utah by approximately 200 miles.

Tuberculosis Outbreak Investigations in the United States, 2002–2008

To understand circumstances of tuberculosis transmission that strain public health resources, we systematically reviewed Centers for Disease Control and Prevention (CDC) staff reports of US outbreaks in which CDC participated during 2002–2008 that involved >3 culture-confirmed tuberculosis cases linked by genotype and epidemiology. Twenty-seven outbreaks, representing 398 patients, were reviewed. Twenty-four of the 27 outbreaks involved primarily US-born patients; substance abuse was another predominant feature of outbreaks. Prolonged infectiousness because of provider- and patient-related factors was common. In 17 outbreaks, a drug house was a notable contributing factor. The most frequently documented intervention to control the outbreak was prioritizing contacts according to risk for infection and disease progression to ensure that the highest risk contacts were completely evaluated. US-born persons with reported substance abuse most strongly characterized the tuberculosis outbreaks in this review. Substance abuse remains one of the greatest challenges to controlling tuberculosis transmission in the United States.

Risk factors for pediatric invasive pneumococcal disease in the Intermountain West, 1996-2002.

PURPOSE In response to concerns that the epidemiology of pediatric invasive pneumococcal disease (IPD) in the Intermountain West (i.e., Utah, Idaho, Wyoming, Montana, and parts of Arizona and Nevada) was poorly understood and might differ from elsewhere in the United States, a case-control study was undertaken to determine factors associated with IPD during 1996-2002. METHODS A telephone questionnaire was administered to parents of children comprising 120 cases identified through hospital records and to parents of 156 age-matched controls located by random-digit dialing. The unit of analysis was each matched case-control set. RESULTS Underlying chronic illness was reported for 32 (27%) of the cases. For previously healthy children, breastfeeding had a protective benefit (adjusted odds ratio: 0.2; 95% confidence interval [CI], 0.1-0.6), while a history of tympanostomy tube surgery was a risk factor (adjusted odds ratio: 12.6; 95% CI, 1.5-107.3). CONCLUSIONS The presence of an underlying chronic illness was the strongest risk factor for IPD. Except for a history of tympanostomy tube surgery, the factors associated with IPD in this investigation were similar to those reported from other geographic regions. Tympanostomy surgery might serve as a surrogate indicator for predisposition to recurrent otitis media or decreased ability to clear pneumococcal infection, raising risk for invasive disease. Pediatric clinicians should continue to encourage breastfeeding, and continued emphasis on pneumococcal vaccination should help prevent IPD.

Using statistical methods and genotyping to detect tuberculosis outbreaks

BackgroundEarly identification of outbreaks remains a key component in continuing to reduce the burden of infectious disease in the United States. Previous studies have applied statistical methods to detect unexpected cases of disease in space or time. The objectives of our study were to assess the ability and timeliness of three spatio-temporal methods to detect known outbreaks of tuberculosis.MethodsWe used routinely available molecular and surveillance data to retrospectively assess the effectiveness of three statistical methods in detecting tuberculosis outbreaks: county-based log-likelihood ratio, cumulative sums, and a spatial scan statistic.ResultsOur methods identified 8 of the 9 outbreaks, and 6 outbreaks would have been identified 1–52 months (median = 10 months) before local public health authorities identified them. Assuming no delays in data availability, 46 (59.7%) of the 77 patients in the 9 outbreaks were identified after our statistical methods would have detected the outbreak but before local public health authorities became aware of the problem.ConclusionsStatistical methods, when applied retrospectively to routinely collected tuberculosis data, can successfully detect known outbreaks, potentially months before local public health authorities become aware of the problem. The three methods showed similar results; no single method was clearly superior to the other two. Further study to elucidate the performance of these methods in detecting tuberculosis outbreaks will be done in a prospective analysis.

Tuberculosis among healthcare workers, United States, 1995-2007.

OBJECTIVE We examined surveillance data to describe the epidemiology of tuberculosis (TB) among healthcare workers (HCWs) in the United States during the period 1995-2007. DESIGN Cross-sectional descriptive analysis of existing surveillance data. SETTING AND PARTICIPANTS TB cases reported to the Centers for Disease Control and Prevention from the 50 states and the District of Columbia from 1995 through 2007. RESULTS Of the 200,744 reported TB cases in persons 18 years of age or older, 6,049 (3%) occurred in individuals who were classified as HCWs. HCWs with TB were more likely than other adults with TB to be women (unadjusted odds ratio [95% confidence interval], 4.1 [3.8-4.3]), be foreign born (1.3 [1.3-1.4]), have extrapulmonary TB (1.6 [1.5-1.7]), and complete TB treatment (2.5 [2.3-2.8]). CONCLUSIONS Healthcare institutions may benefit from intensifying TB screening of HCWs upon hire, especially persons from countries with a high incidence of TB, and encouraging treatment for latent TB infection among HCWs to prevent progression to TB disease.

Public health response to a multidrug-resistant tuberculosis outbreak among Guatemalans in Tennessee, 2007.

Background: In June 2007, the Tennessee Department of Health notified the Centers for Disease Control and Prevention of four multidrug-resistant tuberculosis (MDR TB) cases in individuals of Guatemalan descent, and requested onsite epidemiologic assistance to investigate this outbreak. Methods: A case was defined as either culture-confirmed MDR TB with a drug-susceptibility pattern closely resembling that of the index case, or a clinical diagnosis of active TB disease and corroborated contact with a person with culture-confirmed MDR TB. Medical records were reviewed, and patients and their contacts were interviewed. Results: Five secondary TB cases were associated with the index case. Of 369 contacts of the index case, 189 (51%) were evaluated. Of those, 97 (51%) had positive tuberculin skin test (TST) results, 79 (81%) began therapy for latent TB infection (LTBI), and 38 (48%) completed LTBI therapy. Conclusion: Despite consistent follow up by public health officials, a low proportion of patients diagnosed with LTBI completed therapy. Clinicians and public health practitioners who serve immigrant communities should be vigilant for MDR TB.

Characteristics of Tuberculosis Cases that Started Outbreaks in the United States, 2002–2011

A review of 26 tuberculosis outbreaks in the United States (2002–2011) showed that initial source case-patients had long infectious periods (median 10 months) and were characterized by substance abuse, incarceration, and homelessness. Improved timeliness of diagnosis and thorough contact investigations for such cases may reduce the risk for outbreaks.

Prioritizing Tuberculosis Clusters by Genotype for Public Health Action, Washington, USA

Groups of tuberculosis cases with indistinguishable Mycobacterium tuberculosis genotypes (clusters) might represent recent transmission. We compared geospatial concentration of genotype clusters with independent priority rankings determined by local public health officials; findings were highly correlated. Routine use of geospatial statistics could help health departments identify recent disease transmission.