Terrestrial Bird Migration and West Nile Virus Circulation, United States.

Host migration and emerging pathogens are strongly associated, especially with regard to zoonotic diseases. West Nile virus (WNV), a mosquitoborne pathogen capable of causing severe, sometimes fatal, neuroinvasive disease in humans, is maintained in highly mobile avian hosts. Using phylogeographic approaches, we investigated the relationship between WNV circulation in the United States and the flight paths of terrestrial birds. We demonstrated southward migration of WNV in the eastern flyway and northward migration in the central flyway, which is consistent with the looped flight paths of many terrestrial birds. We also identified 3 optimal locations for targeted WNV surveillance campaigns in the United States-Illinois, New York, and Texas. These results illustrate the value of multidisciplinary approaches to surveillance of infectious diseases, especially zoonotic diseases.

West Nile Virus Outbreak in Houston and Harris County, Texas, USA, 2014.

Since 2002, West Nile virus (WNV) has been detected every year in Houston and the surrounding Harris County, Texas. In 2014, the largest WNV outbreak to date occurred, comprising 139 cases and causing 2 deaths. Additionally, 1,286 WNV-positive mosquito pools were confirmed, the most reported in a single mosquito season.

Continued evolution of West Nile virus, Houston, Texas, USA, 2002-2012.

We investigated the genetics and evolution of West Nile virus (WNV) since initial detection in the United States in 1999 on the basis of continual surveillance studies in the Houston, Texas, USA, metropolitan area (Harris County) as a surrogate model for WNV evolution on a national scale. Full-length genomic sequencing of 14 novel 2010-2012 WNV isolates collected from resident birds in Harris County demonstrates emergence of 4 independent genetic groups distinct from historical strains circulating in the greater Houston region since 2002. Phylogenetic and geospatial analyses of the 2012 WNV isolates indicate closer genetic relationship with 2003-2006 Harris County isolates than more recent 2007-2011 isolates. Inferred monophyletic relationships of these groups with several 2006-2009 northeastern US isolates supports potential introduction of a novel WNV strain in Texas since 2010. These results emphasize the need to maintain WNV surveillance activities to better understand WNV transmission dynamics in the United States.

Characterization of Three Novel Viruses from the Families Nyamiviridae, Orthomyxoviridae, and Peribunyaviridae, Isolated from Dead Birds Collected during West Nile Virus Surveillance in Harris County, Texas.

This report describes and characterizes three novel RNA viruses isolated from dead birds collected during West Nile virus surveillance in Harris County, TX, USA (the Houston metropolitan area). The novel viruses are identified as members of the families Nyamaviridae, Orthomyxoviridae, and Peribunyaviridae and have been designated as San Jacinto virus, Mason Creek virus, and Buffalo Bayou virus, respectively. Their potential public health and/or veterinary importance are still unknown.

Differential Vector Competency of Aedes albopictus Populations from the Americas for Zika Virus.

To evaluate the potential role of Aedes albopictus (Skuse) as a vector of Zika virus (ZIKV), colonized mosquitoes of low generation number (≤ F5) from Brazil, Houston, and the Rio Grande Valley of Texas engorged on viremic mice infected with ZIKV strains originating from Senegal, Cambodia, Mexico, Brazil, or Puerto Rico. Vector competence was established by monitoring infection, dissemination, and transmission potential after 3, 7, and 14 days of extrinsic incubation. Positive saliva samples were assayed for infectious titer. Although all three mosquito populations were susceptible to all ZIKV strains, rates of infection, dissemination, and transmission differed among mosquito and virus strains. Aedes albopictus from Salvador, Brazil, were the least efficient vectors, demonstrating susceptibility to infection to two American strains of ZIKV but failing to shed virus in saliva. Mosquitoes from the Rio Grande Valley were the most efficient vectors and were capable of shedding all three tested ZIKV strains into saliva after 14 days of extrinsic incubation. In particular, ZIKV strain DakAR 41525 (Senegal 1954) was significantly more efficient at dissemination and saliva deposition than the others tested in Rio Grande mosquitoes. Overall, our data indicate that, while Ae. albopictus is capable of transmitting ZIKV, its competence is potentially dependent on geographic origin of both the mosquito population and the viral strain.

2014: A Record-Breaking Year for West Nile Virus Positive Mosquito Pools in Harris County and the City of Houston, Texas.

In the 14 years since the emergence of West Nile virus (WNV) in Harris County and the city of Houston, Texas, the number of mosquitoes infected with the virus has fluctuated with several high and low count years. During this 14-year period, mosquito surveillance operational areas in Harris County were expanded from 248 to 268 and the distribution of the virus activity in mosquitoes varied from year to year. Operational areas with WNV infected mosquitoes increased from 137 in 2002 to 197 in 2006, decreased to 71 areas in 2007, and to an all-time low of 18 in 2008. The number increased to 78 areas in 2009, 96 in 2010, 133 in 2011, and 177 in 2012, but fell to 73 in 2013. However, 234 areas were confirmed in 2014, and only 138 in 2015. The WNV transmission was high in 2002 with 227 WNV positive mosquito pools. The number of positive mosquitoes remained elevated for a number of years and then declined from 2007 to 2010. Three record high years for WNV activity were: 2005, 2006, and 2011 with 698, 838, and 605 confirmed positive mosquito pools, respectively. Viral activity declined in 2012, followed by a marked decline in 2013 with only 147 WNV positive mosquito pools. In 2014, a record-breaking number of 1,286 WNV positive mosquito pools were confirmed in Harris County and the city of Houston, the most ever in a single season, while 406 were confirmed in 2015.

Identification of dengue fever cases in Houston, Texas, with evidence of autochthonous transmission between 2003 and 2005.

Houston, Texas, maintains an environment conducive to dengue virus (DENV) emergence; however, surveillance is passive and diagnostic testing is not readily available. To determine if DENV is present in the area, we tested 3768 clinical specimens (2138 cerebrospinal fluid [CSF] and 1630 serum) collected from patients with suspected mosquito-borne viral disease between 2003 and 2005. We identified 47 immunoglobulin M (IgM)-positive dengue cases, including two cases that were positive for viral RNA in serum for dengue serotype 2. The majority of cases did not report any history of travel outside the Houston area prior to symptom onset. The epidemic curve suggests an outbreak occurred in 2003 with continued low-level transmission in 2004 and 2005. Chart abstractions were completed for 42 of the 47 cases; 57% were diagnosed with meningitis and/or encephalitis, and 43% met the case definition for dengue fever. Two of the 47 cases were fatal, including one with illness compatible with dengue shock syndrome. Our results support local transmission of DENV during the study period. These findings heighten the need for dengue surveillance in the southern United States.

Effect of rosuvastatin on cytokines after traumatic head injury.

OBJECT: The favorable effect of statin treatment after traumatic brain injury (TBI) has been shown in animal studies and is probably true in humans as well. The objective of this study was to determine whether acute statin treatment following TBI could reduce inflammatory cytokines and improve functional outcomes in humans. METHODS: The authors performed a double-blind randomized clinical trial in patients with moderate to severe TBI. Exclusion criteria were as follows: prior severe disability; use of modifiers of statin metabolism; multisystem trauma; prior use of mannitol, barbiturates, corticosteroids, or calcium channel blockers; isolated brainstem lesions; allergy to statins; previous hepatopathy or myopathy; previous treatment at another clinic; and pregnancy. Patients were randomly selected to receive 20 mg of rosuvastatin or placebo for 10 days. The main goal was to determine the effect of rosuvastatin on plasma levels of tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and IL-10 after 72 hours of TBI. Amnesia, disorientation, and disability were assessed 3 and 6 months after TBI. RESULTS: Thirty-six patients were analyzed according to intention-to-treat analysis; 19 patients received rosuvastatin and 17 received placebo. The best-fit mixed model showed a significant effect of rosuvastatin on the reduction of tumor necrosis factor-α levels (p = 0.004). Rosuvastatin treatment did not appear to affect the levels of IL-1ß, IL-6, and IL-10. The treatment was associated with a reduction in disability scores (p = 0.03), indicating a favorable functional outcome. Life-threatening adverse effects were not observed. CONCLUSIONS: The authors' data suggest that statins may induce an antiinflammatory effect and may promote recovery after TBI. The role of statins in TBI therapy should be confirmed in larger clinical trials.

Amoebic toxic colitis: analysis of factors related to mortality.

BACKGROUND: Toxic or fulminant colitis due to Entamoeba histolytica infrequently presents but is very serious. Unfortunately, there are numerous contradictory factors related to mortality. METHODS: We analyzed several cases of E. histolytica infection to determine the factors related to mortality. We included patients >15 years of age who were histopathologically diagnosed with amoebic toxic colitis and treated from January 2000 through December 2006. We evaluated demographic, clinical, laboratorial, surgical, and histopathological characteristics. RESULTS: We examined 24 patients and recorded 12 deaths (50%). Twenty patients underwent surgery within a mean time of 24 hours (range: 8-120 hours). Tenesmus and intestinal perforation were determined to be statistically significant (P<0·05) by univariate analysis. Three models of logistic regression were able to determine three statistically significant factors that affected mortality: (1) tenesmus and a lymphocyte count <1·5×10(3) cell/µl; 2) depth of invasion beyond the mucosa and a lymphocyte count <1·5×10(3) cell/µl; 3) time spent with symptoms and perforation. CONCLUSIONS: The mortality rate determined in this study is similar to previously reported series. A low lymphocyte count, significant depth of invasion, and intestinal perforation were determined to be the factors related to increased mortality, while tenesmus and limited amount of time spent with symptoms were associated with survival. Quick diagnosis and appropriate treatment are important factors that reduce mortality.

Prognostic indications of the failure to treat amoebic liver abscesses.

OBJECTIVES: To identify the variables that predict the failure to treat amoebic liver abscesses. METHODS: We prospectively carried out a case-control study on a cohort of patients who had been diagnosed with amoebic liver abscesses using clinical, ultrasonic, and serologic methods. Patients with pyogenic abscesses, negative ELISA tests for amoebiasis, immunosuppression status, or previous abdominal surgery were excluded. All patients received metronidazole, and those who demonstrated 4 days of unfavorable clinical responses received percutaneous or surgical draining of the abscess. Demographic, laboratory, and ultrasonographic characteristics were assessed as prognostic indications of failure. RESULTS: Of 40 patients with amoebic liver abscess, 24 (mean age: 36·7±11·2 years) responded to medical treatment and 16 (41·8±11·6 years) required drainage, including 14 patients who underwent percutaneous drainage and two patients who required surgery. The albumin level, abscess volume, abscess diameter, and alkaline phosphatase level were all statistically significant (P<0·05) on the bivariate analysis. The highest (>99%) sensitivity and negative predictive value were observed for an abscess volume >500 ml and diameter >10 cm, while the best specificity and positive predictive value were achieved with the combination of low serum albumin level, high alkaline phosphatase level, and large abscess volume or diameter. CONCLUSIONS: The prognostic indications of the failure to treat amoebic liver abscesses include low albumin, high alkaline phosphatase, and large abscess volume or diameter. The combination of these variables is a useful and easy tool for determining appropriate therapy.

Experience with a new design of endoretractor for gasless laparoscopic cholecystectomy.

BACKGROUND: Cholecystectomy has replaced open surgery and is regarded as the standard procedure today. The pneumoperitoneum needed to create working space can induce cardiovascular changes. Gasless laparoscopic surgery is effective; we evaluate a new retractor design. METHODS: Patients older than 15 years with elective cholecystectomy and American Society of Anesthesiology I-II were consequently assigned to conventional or gasless surgery. We evaluated surgical time, hemodynamic stability, hours of hospital stay, and days of recuperation. RESULTS: We analyzed 22 cholecystectomies, 10 by the gasless technique and 12 by gas laparoscopy. We did not observe significant differences in surgical time, length of hospital stay, or days of recuperation. However, surgical exposition time was longer in the retractor group than was expected by chance (P<0.05). Hemodynamic stability was similar between the groups. CONCLUSIONS: Similar surgical and recuperation times and length of hospital stay were observed. Our design is comparable with conventional laparoscopic surgery despite longer surgical exposition time.