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Objective Magnesium historically has been used for treatment and/or prevention of eclampsia or preterm labor. More recently, antepartum magnesium sulfate has been suggested for prevention of cerebral palsy in preterm infants. Although adverse effects and toxicity of magnesium in pregnant women are well known, the fetal-neonatal effects of magnesium are less clear. The objective of this study was to evaluate the effects of magnesium on the newborn infant. Study Design This is a retrospective cohort analysis of women who received antepartum magnesium sulfate for prevention or treatment of eclampsia. Magnesium sulfate was given intravenously beginning with a 6-g dose, followed by 2- to 3-g/h infusion. Newborn hypotonia was diagnosed if an infant exhibited less than normal tone/ activity upon admission to the nursery. Results Between January 2000 and February 2009, a total of 6654 women with preeclampsia were treated with intravenous magnesium sulfate as described; 88 (6%) of the infants were diagnosed with hypotonia. Lower 1-minute and 5-minute Apgar scores, intubation in the delivery room, admission to special care nursery, and hypotonia were all significantly increased as maternal serum magnesium concentrations increased before birth. Conclusion Several neonatal complications are significantly related to increasing concentrations of magnesium in the maternal circulation. [ABSTRACT FROM AUTHOR]

Objective To evaluate total calculated blood loss at the time of severe obstetric hemorrhage. Study Design This is a prospective observational study of women with obstetric hemorrhage. Women who received a blood transfusion for hypovolemia and those in which a body mass index (BMI) could be calculated were included. Total blood volume lost was calculated. Blood loss was analyzed in relation to maternal size as reflected in the BMI. Results Fourteen hundred forty-three women meeting inclusion criteria delivered at our hospital between March 2002 and June 2006. The median calculated volume of blood lost was 3529 mL, and 93% of women sustained losses ≥3000 mL. The blood loss sufficient to provoke signs and symptoms of hypovolemia was proportional to the woman's BMI. Conclusion Women who develop hypovolemia during childbirth have suffered very large losses of blood, and infusion of blood products is required to restore circulation and prevent further morbidity. [ABSTRACT FROM AUTHOR]

The article presents a study which examines the demographic and clinical features of hantavirus pulmonary syndrome (HPS) from 1993-2006 in Texas. Case report forms and medical records of the patients submitted to the Department of State Health Services were reviewed. Respiratory symptoms, common laboratory features and distribution of the disease are described.

Background: In 2002, West Nile virus (WNV) first appeared in Texas. Surveillance data were retrospectively examined to explore the temporal and spatial characteristics of the Texas equine WNV epidemic in 2002. Using Geographic Information Systems (GIS) and the Spatial and Space-Time Scan (SaTScan) statistics, we analyzed 1421 of the reported equine WNV cases from six contiguous state Health Service Regions (HSRs), comprising 158 counties, in western, northern, central and eastern Texas. Results: Two primary epidemic peaks occurred in Epidemiological (Epi) week 35 (August 25 to 31) and Epi week 42 (October 13 to 19) of 2002 in the western and eastern part of the study area, respectively. The SaTScan statistics detected nine non-random spatio-temporal equine case aggregations (mini-outbreaks) and five unique high-risk areas imbedded within the overall epidemic. Conclusion: The 2002 Texas equine WNV epidemic occurred in a bi-modal pattern. Some "local hot spots" of the WNV epidemic developed in Texas. The use of GIS and SaTScan can be valuable tools in analyzing on-going surveillance data to identify high-risk areas and shifts in disease clustering within a large geographic area. Such techniques should become increasingly useful and important in future epidemics, as decisions must be made to effectively allocate limited resources. [ABSTRACT FROM AUTHOR]

A jackrabbit die-off near a metropolitan airport was observed by an airport contractor. Further investigation determined that this die-off was probably due to epizootic tularemia. Because of proximity to areas of heavy human traffic and fears of transmission of tularemia to humans, the local health district and department of emergency management organized a multiagency response involving local animal control, environmental health, public health, law enforcement, and airport personnel, in addition to state and federal agencies. The tularemia epizootic subsequently ended, and no cases of human tularemia occurred. In our after-action analysis, we identified several lessons learned: the importance of animal illness surveillance, which can serve as a warning for potential human illness and epidemic; the usefulness of pre-event planning, training, and exercises in facilitating a coordinated response; the usefulness of an effective communication system with the healthcare community; the importance of responders being familiar with Centers for Disease Control and Prevention (CDC) Category A bioterrorism agents when considering a rapid response; and the fact that attempts at environmental control may result in perturbations in animal populations with unintended consequences.

Background: In 2002, West Nile virus (WNV) first appeared in Texas. Surveillance data were retrospectively examined to explore the temporal and spatial characteristics of the Texas equine WNV epidemic in 2002. Using Geographic Information Systems (GIS) and the Spatial and Space-Time Scan (SaTScan) statistics, we analyzed 1421 of the reported equine WNV cases from six contiguous state Health Service Regions (HSRs), comprising 158 counties, in western, northern, central and eastern Texas., Results: Two primary epidemic peaks occurred in Epidemiological (Epi) week 35 (August 25 to 31) and Epi week 42 (October 13 to 19) of 2002 in the western and eastern part of the study area, respectively. The SaTScan statistics detected nine non-random spatio-temporal equine case aggregations (mini-outbreaks) and five unique high-risk areas imbedded within the overall epidemic., Conclusion: The 2002 Texas equine WNV epidemic occurred in a bi-modal pattern. Some "local hot spots" of the WNV epidemic developed in Texas. The use of GIS and SaTScan can be valuable tools in analyzing on-going surveillance data to identify high-risk areas and shifts in disease clustering within a large geographic area. Such techniques should become increasingly useful and important in future epidemics, as decisions must be made to effectively allocate limited resources.

Purpose: Arboviral diseases, such as West Nile virus (WNV) epizootics, tend to be geographically unique because of the biomes that support the vector(s) and reservoir host(s). Understanding such details aids in preventive efforts. We studied the 2003 epidemic of human West Nile neuroinvasive disease (WNND) in Texas because it initially appeared that incidence was not uniform across regions of the state., Methods: The epidemic was described by age, sex, and region of residence. These variables were used to compare age-specific incidence, standardized cumulative incidence, and age-adjusted relative risk (RR). We verified case data and used routine software, with population estimates from the US Census Bureau., Results: Regardless of sex, risk increased with age. Males had the greater risk (RR, 1.69); however, males aged 5 to 17 years had the greatest RR. Of the five regions compared, two posed more (RRs, 7.98 and 2.14) and one posed less (RR, 0.40) risk than the remainder of the state. Proportions of Culex vector species differed significantly between regions., Conclusions: During 2003, the risk for WNND varied considerably across Texas. This suggests that various risks for WNV infection deserve additional research for preventive interventions to be regionally appropriate and effective.

To determine whether swift foxes (Vulpes velox) could facilitate transmission of Yersinia pestis to uninfected black-tailed prairie dog (Cynomys ludovicianus) colonies by acquiring infected fleas, ectoparasite and serologic samples were collected from swift foxes living adjacent to prairie dog towns during a 2004 plague epizootic in northwestern Texas, USA. A previous study (1999-2001) indicated that these swift foxes were infested almost exclusively with the flea Pulex irritans. Black-tailed prairie dogs examined from the study area harbored only Pulex simulans and Oropsylla hirsuta. Although P. irritans was most common, P. simulans and O. hirsuta were collected from six swift foxes and a single coyote (Canis latrans) following the plague epizootic. Thus, both of these canids could act as transport hosts (at least temporarily) of prairie dog fleas following the loss of their normal hosts during a plague die-off. All six adult swift foxes tested positive for antibodies to Y. pestis. All 107 fleas from swift foxes tested negative for Y. pestis by mouse inoculation. Although swift foxes could potentially carry Y. pestis to un-infected prairie dog colonies, we believe they play only a minor role in plague epidemiology, considering that they harbored just a few uninfected prairie dog fleas (P. simulans and O. hirsuta).

Objective: To describe naturally occurring birth patterns in low-risk women with singleton gestations and spontaneous onset of labor at term., Materials and Methods: The timing of birth of women who delivered in the low-risk labor unit at Parkland Hospital, Dallas, Texas, between January 1, 2000, to December 31, 2000, was analyzed. Women admitted to this unit were between 36(0/7) and 41(6/7) weeks of gestation, were in spontaneous labor, and had a singleton gestation. Women with contraindications to labor, significant medical problems, a known fetal anomaly, and stillbirths were excluded from analysis. The frequency of birth was analyzed in relation to the time of day, day of week, and month of the year., Results: Low-risk women (n = 6608) met the study criteria and were included in the analysis. No association was found between the day of the week and the frequency of births (P =.31). Births were most common between the hours of 1 to 2 pm and least common between the hours of 10:00 to 12:00 hours (Central Standard Time, P =.04). Births were more common in the fall, September through November, and least common in the winter, December through February. Daylight Saving Time did not affect these results., Conclusion: Birth after the spontaneous onset of labor is most common in the early afternoon, and most births occur in the fall. There is no natural association between spontaneous birth in low-risk women and the day of the week., Level of Evidence: II-2

Objective: To measure the rate of hepatitis B (HBV) transmission from chronic HBV carriers to breast-fed infants after immunoprophylaxis., Methods: Since 1992, information on women with HBV during pregnancy has been collected in a prospective longitudinal study. Those HBV carriers and their infants participating in a county HBV immunoprophylaxis program were identified. Infants were followed for up to 15 months and examined for hepatitis B infection by hepatitis B surface antigen (HBsAg)., Results: A total of 369 infants born to women with chronic HBV met the inclusion criteria and received hepatitis B immune globulin at birth and the full course of the hepatitis B vaccine series. We compared 101 breast-fed infants with 268 formula-fed infants. There was no significant difference between the two groups with respect to the number of women who were positive for hepatitis B e antigen (HBeAg) (22% versus 26%, P =.51). Three women in the breast-feeding group had liver transaminase abnormalities, compared with six women in the formula-feeding group (P =.29). Overall, there were nine cases of HBV infection transmission (2.4%). None of the 101 breast-fed infants and nine formula-fed infants (3%) were positive for HBsAg after the initial vaccination series (P =.063). The mean length of time for breast-feeding was 4.9 months (range 2 weeks to 1 year)., Conclusion: With appropriate immunoprophylaxis, including hepatitis B immune globulin and hepatitis B vaccine, breast-feeding of infants of chronic HBV carriers poses no additional risk for the transmission of the hepatitis B virus.