Correction: Diversity, distribution and natural Leishmania infection of sand flies from communities along the Interoceanic Highway in the Southeastern Peruvian Amazon

[This corrects the article DOI: 10.1371/journal.pntd.0009000.].

Diversity, distribution and natural Leishmania infection of sand flies from communities along the Interoceanic Highway in the Southeastern Peruvian Amazon

The Peruvian-Brazilian border is a highly endemic tegumentary leishmaniasis region in South America. The interoceanic highway is a commercial route that connects Peru and Brazil through Madre de Dios and has raised concerns about its impact on previously undisturbed areas. In order to assess leishmaniasis transmission risk along this highway, we conducted a surveillance study of the sand fly populations in this area. Sand flies were collected between 2009 and 2010 along transects at 200 m, 600 m and 1000 m from six study sites located along the highway (Iberia, La Novia, Alto Libertad, El Carmen, Florida Baja, Mazuko and Mavila) and an undisturbed area (Malinowski). Collected specimens were identified based on morphology and non-engorged females of each species were pooled and screened by kinetoplast PCR to detect natural Leishmania infections. A total of 9,023 specimens were collected belonging to 54 different Lutzomyia species including the first report of Lu. gantieri in Peru. Four species accounted for 50% of all specimens (Lutzomyia carrerai carrerai, Lu. davisi, Lu. shawi and Lu. richardwardi). El Carmen, Alto Libertad, Florida Baja and Malinowski presented higher Shannon diversity indexes (H = 2.36, 2.30, 2.17 and 2.13, respectively) than the most human disturbed sites of Mazuko and La Novia (H = 1.53 and 1.06, respectively). PCR detected 10 positive pools belonging to Lu. carrerai carrerai, Lu. yuilli yuilli, Lu. hirsuta hirsuta, Lu. (Trichophoromyia) spp., and Lu. (Lutzomyia) spp. Positive pools from 1,000 m transects had higher infectivity rates than those from 600 m and 200 m transects (9/169 = 5.3% vs 0/79 = 0% and 1/127 = 0.8%, p = 0.018). El Carmen, accounted for eight out of ten positives whereas one positive was collected in Florida Baja and Mazuko each. Our study has shown differences in sand fly diversity, abundance and species composition across and within sites. Multiple clustered Lutzomyia pools with natural Leishmania infection suggest a complex, diverse and spotty role in leishmaniasis transmission in Madre de Dios, with increased risk farther from the highway.

Prevalence of Escherichia coli O157:H7 From House Flies (Diptera: Muscidae) and Dairy Samples in North Central Florida1

La detección de Escherichia coli O157:H7 en las lecherías es importante para mejorar la seguridad de los productos lácteos, y se ha llevado a cabo principalmente mediante el aislamiento de las bacterias a partir de las muestras de estiércol. Sin embargo, los componentes biliares presentes en el estiércol complica la identificación genética utilizando la técnica del PCR, y el aislamiento microbiológico se dificulta por la presencia de bacterias competidoras que comparten características microbiológicas similares. El aislamiento de E. coli O157:H7 a partir de la mosca doméstica evita las dificultades asociadas con el estiércol del ganado. El aislamiento de patógenos a partir de las moscas domésticas proporciona información adicional sobre el potencial impacto epidemiológico de la dispersión de la mosca doméstica en la distribución de patógenos, ya que las moscas domésticas se dispersan desde las lecherías donde la E. coli O157:H7 existe en forma endémica en el ganado. En este estudio, se encontró que las moscas domésticas son 2,6 veces más sensibles para la detección de E. coli O157:H7 en las lecherías. Las moscas son más fáciles de capturar y manejar que el estiércol, y deberían ser utilizadas en cualquier ensayo para detectar E. coli O157:H7 en las lecherías y otros establecimientos.

Detection of Rickettsia parkeri from within Piura, Peru, and the first reported presence of Candidatus Rickettsia andeanae in the tick Rhipicephalus sanguineus

Domestic farm animals (n=145) were sampled for the presence of ectoparasites in northwestern Peru during March, 2008. Ninety domestic animals (62%) were positive for the presence of an ectoparasite(s) and produced a total collection of the following: 728 ticks [Amblyomma maculatum, Anocentor nitens, Rhipicephalus (Boophilus) microplus, Rhipicephalus sanguineus, and Otobius megnini], 12 lice (Haematopinus suis), and 3 fleas (Ctenocephalides felis). A Rickettsia genus-specific qPCR assay was performed on nucleic acid preparations of the collected ectoparasites that resulted in 5% (37/743, 35 ticks and 2 fleas) of the ectoparasites positive for the presence of Rickettsia. DNA from the positive individual ticks was tested with 2 other qPCR assays for the presence of the ompB gene in Candidatus Rickettsia andeanae or Rickettsia parkeri. Candidatus R. andeanae was found in 25 A. maculatum ticks and in two Rh. sanguineus ticks, whereas R. parkeri was detected in 6 A. maculatum ticks. Two A. maculatum were co-infected with both Candidatus R. andeanae and R. parkeri. Rickettsia felis was detected in 2 fleas, Ctenocephalides felis, by multilocus sequence typing of the 17-kD antigen and ompA genes. These findings expand the geographic range of R. parkeri to include Peru as well as expand the natural arthropod vector of Candidatus R. andeanae to include Rhipicephalus sanguineus.

Contact irritant responses of Aedes aegypti Using sublethal concentration and focal application of pyrethroid chemicals

BACKGROUND

Previous studies have demonstrated contact irritant and spatial repellent behaviors in Aedes aegypti following exposure to sublethal concentrations of chemicals. These sublethal actions are currently being evaluated in the development of a push-pull strategy for Ae. aegypti control. This study reports on mosquito escape responses after exposure to candidate chemicals for a contact irritant focused push-pull strategy using varying concentrations and focal application.

METHODS

Contact irritancy (escape) behavior, knockdown and 24 hour mortality rates were quantified in populations of female Ae. aegypti under laboratory conditions and validated in the field (Thailand and Peru) using experimental huts. Evaluations were conducted using varying concentrations and treatment surface area coverage (SAC) of three pyrethroid insecticides: alphacypermethrin, lambacyhalothrin and deltamethrin.

RESULTS

Under laboratory conditions, exposure of Ae. aegypti to alphacypermethrin using the standard field application rate (FAR) resulted in escape responses at 25% and 50% SAC that were comparable with escape responses at 100% SAC. Significant escape responses were also observed at <100% SAC using ½FAR of all test compounds. In most trials, KD and 24 hour mortality rates were higher in mosquitoes that did not escape than in those that escaped. In Thailand, field validation studies indicated an early time of exit (by four hours) and 40% increase in escape using ½FAR of alphacypermethrin at 75% SAC compared to a matched chemical-free control. In Peru, however, the maximum increase in Ae. aegypti escape from alphacypermethrin-treated huts was 11%.

CONCLUSIONS/SIGNIFICANCE

Results presented here suggest a potential role for sublethal and focal application of contact irritant chemicals in an Ae. aegypti push-pull strategy to reduce human-vector contact inside treated homes. However, the impact of an increase in escape response on dengue virus transmission is currently unknown and will depend on rate of biting on human hosts prior to house exiting.

Molecular taxonomy of Anopheles (Nyssorhynchus) benarrochi (Diptera: Culicidae) and malaria epidemiology in southern Amazonian Peru

Anopheline specimens were collected in 2011 by human landing catch, Shannon and CDC traps from the malaria endemic localities of Santa Rosa and San Pedro in Madre de Dios Department, Peru. Most specimens were either Anopheles (Nyssorhynchus) benarrochi B or An. (Nys.) rangeli, confirmed by polymerase chain reaction-restriction fragment length polymorphism-internal transcribed spacer 2 (PCR-RFLP-ITS2) and, for selected individuals, ITS2 sequences. A few specimens from Lupuna, Loreto Department, northern Amazonian Peru, were also identified as An. benarrochi B. A statistical parsimony network using ITS2 sequences confirmed that all Peruvian An. benarrochi B analyzed were identical to those in GenBank from Putumayo, southern Colombia. Sequences of the mtDNA COI BOLD region of specimens from all three Peruvian localities were connected using a statistical parsimony network, although there were multiple mutation steps between northern and southern Peruvian sequences. A Bayesian inference of concatenated Peruvian sequences of ITS2 + COI detected a single clade with very high support for all An. benarrochi B except one individual from Lupuna that was excluded. No samples were positive for Plasmodium by CytB-PCR.

Laparoscopic cholecystectomy in biliary pancreatitis

Laparoscopic cholecystectomy has emerged as the treatment of choice for uncomplicated cholelithiasis. Despite early concerns, many surgeons have applied this new technique to more complicated biliary tract disease states, including biliary pancreatitis. To evaluate the safety of laparoscopic cholecystectomy in this setting, we retrospectively reviewed 29 patients with clinical and laboratory evidence of biliary pancreatitis who underwent this procedure between March 1990 and December 1992. The severity of pancreatitis was determined by Ranson's criteria. Two patients had a Ranson's score of 6, one of 5, one of 4, five scored 3, nine scored 2, nine also scored 1, and two patients scored 0. The mean serum amylase level on admission was 1,610 (range 148 to 7680). All patients underwent laparoscopic cholecystectomy during the same hospital admission for biliary pancreatitis, with the mean time of operation being 5.5 days from admission. Operative time averaged 123 minutes (range 60-220 minutes). Intraoperative cholangiography was obtained in 76 per cent of patients. Three patients had choledocholithiasis on intraoperative cholangiography and were treated with choledochoscopy, laparoscopic common bile duct exploration, and saline flushing of the duct. The mean length of hospital stay was 11 days (range 5-32 days). There were seven postoperative complications requiring prolonged hospitalization with all but one treated non-operatively. One patient with a preoperative Ranson score of 6 developed necrotizing pancreatitis and subsequently required operative pancreatic debridement and drainage. There were no deaths in this series and no postoperative wound infections. The average recovery period for return to work was 2 weeks. These statistics compare favorably with literature reports for open cholecystectomy in biliary pancreatitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Safety, efficacy, cost, and morbidity of laparoscopic versus open cholecystectomy: a prospective analysis of 228 consecutive patients

Laparoscopic cholecystectomy has become the procedure of choice in most hospitals for the resolution of surgically treatable gallbladder disease. Few reports address the results of laparoscopic cholecystectomy in comparison to open cholecystectomy during the same time interval within the same institution. One hundred ninety-six laparoscopic cholecystectomies were performed from April 1990 through February 1991. Initial patient selection was restricted to elective procedures for chronic cholecystitis with expanded indications as experience was gained. Of the 196 cases, 11 required conversion to open cholecystectomy, leaving 185 laparoscopic cholecystectomies for comparison. During the same period, 82 open cholecystectomies were performed. Thirty-nine of these were complicated cases and would not have been considered for laparoscopic cholecystectomy early in the study, leaving 43 routine open cholecystectomies for comparative purposes. In the laparoscopic group, 1.1 per cent of the patients had major operative complications as opposed to the open group, which had none. There were no common bile duct injuries in either group. To provide a true cost-benefit analysis, a group of patients was identified that would qualify for elective, same-day admission for either an open or laparoscopic procedure. Laparoscopic cholecystectomy (LC) was performed on 70 patients, and open cholecystectomy (OC) was performed on 26 patients. A comparison of data from these groups showed no significant difference in age or sex. Hospitalization costs averaged $5,390 for the LC group versus $5,392 for the OC group. Postoperative hospital stay averaged 1.3 days for the LC group versus 3.7 days for the OC group (P < 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)