Toxoplasmosis hospitalizations in the United States, 2008, and trends, 1993-2008.

BACKGROUND: Toxoplasmosis-related hospitalizations often occur in persons with human immunodeficiency virus (HIV) infection and other causes of immunosuppression. METHODS: Using the National Inpatient Sample (NIS) from the Healthcare Cost and Utilization Project, we examined trends in toxoplasmosis-related hospitalizations by HIV infection status from 1993 through 2008, and rates by sex and race or ethnicity in 2008. The NIS is designed to represent a 20% sample of US community hospitals and currently includes information on up to 8 million discharges per year from ∼1000 hospitals. We used International Classification of Diseases, Ninth Revision, Clinical Modification codes 130-130.9 for toxoplasmosis and 042-044/795.8/795.71/V08 for HIV infection. RESULTS: Estimated HIV-associated toxoplasmosis hospitalizations increased from 9395 in 1993 to 10583 in 1995 (P = .0002), then dropped to 3643 in 2001 (P < .0001), with similar levels thereafter. The rate of HIV-associated toxoplasmosis hospitalizations among all HIV-related hospitalizations decreased from 3.33% in 1993 to 1.25% in 2008 (P < .0001). Estimated non-HIV-associated toxoplasmosis hospitalizations were less variable from 1993 to 2008 (range, 386-819; 0.0020% in 1993, 0.0015% in 2008). In 2008, the rates of both HIV- and non-HIV-associated toxoplasmosis hospitalizations were higher in Hispanic persons than in white persons. CONCLUSIONS: HIV-associated toxoplasmosis hospitalizations dropped markedly after 1995 when highly active antiretroviral therapy was introduced; however, hospitalizations decreased relatively little after 2000, suggesting late diagnosis of some HIV-infected persons or antiretroviral therapy failure. Non-HIV-associated toxoplasmosis hospitalizations have been more stable. The rates of toxoplasmosis-related hospitalizations varied markedly among racial and ethnic groups.

Routine delivery of artemisinin-based combination treatment at fixed health facilities reduces malaria prevalence in Tanzania: an observational study.

BACKGROUND: Artemisinin-based combination therapy (ACT) has been promoted as a means to reduce malaria transmission due to their ability to kill both asexual blood stages of malaria parasites, which sustain infections over long periods and the immature derived sexual stages responsible for infecting mosquitoes and onward transmission. Early studies reported a temporal association between ACT introduction and reduced malaria transmission in a number of ecological settings. However, these reports have come from areas with low to moderate malaria transmission, been confounded by the presence of other interventions or environmental changes that may have reduced malaria transmission, and have not included a comparison group without ACT. This report presents results from the first large-scale observational study to assess the impact of case management with ACT on population-level measures of malaria endemicity in an area with intense transmission where the benefits of effective infection clearance might be compromised by frequent and repeated re-infection. METHODS: A pre-post observational study with a non-randomized comparison group was conducted at two sites in Tanzania. Both sites used sulphadoxine-pyrimethamine (SP) monotherapy as a first-line anti-malarial from mid-2001 through 2002. In 2003, the ACT, artesunate (AS) co-administered with SP (AS + SP), was introduced in all fixed health facilities in the intervention site, including both public and registered non-governmental facilities. Population-level prevalence of Plasmodium falciparum asexual parasitaemia and gametocytaemia were assessed using light microscopy from samples collected during representative household surveys in 2001, 2002, 2004, 2005 and 2006. FINDINGS: Among 37,309 observations included in the analysis, annual asexual parasitaemia prevalence in persons of all ages ranged from 11% to 28% and gametocytaemia prevalence ranged from <1% to 2% between the two sites and across the five survey years. A multivariable logistic regression model was fitted to adjust for age, socioeconomic status, bed net use and rainfall. In the presence of consistently high coverage and efficacy of SP monotherapy and AS + SP in the comparison and intervention areas, the introduction of ACT in the intervention site was associated with a modest reduction in the adjusted asexual parasitaemia prevalence of 5 percentage-points or 23% (p < 0.0001) relative to the comparison site. Gametocytaemia prevalence did not differ significantly (p = 0.30). INTERPRETATION: The introduction of ACT at fixed health facilities only modestly reduced asexual parasitaemia prevalence. ACT is effective for treatment of uncomplicated malaria and should have substantial public health impact on morbidity and mortality, but is unlikely to reduce malaria transmission substantially in much of sub-Saharan Africa where individuals are rapidly re-infected.

Causes of outbreaks associated with drinking water in the United States from 1971 to 2006.

Since 1971, the CDC, EPA, and Council of State and Territorial Epidemiologists (CSTE) have maintained the collaborative national Waterborne Disease and Outbreak Surveillance System (WBDOSS) to document waterborne disease outbreaks (WBDOs) reported by local, state, and territorial health departments. WBDOs were recently reclassified to better characterize water system deficiencies and risk factors; data were analyzed for trends in outbreak occurrence, etiologies, and deficiencies during 1971 to 2006. A total of 833 WBDOs, 577,991 cases of illness, and 106 deaths were reported during 1971 to 2006. Trends of public health significance include (i) a decrease in the number of reported outbreaks over time and in the annual proportion of outbreaks reported in public water systems, (ii) an increase in the annual proportion of outbreaks reported in individual water systems and in the proportion of outbreaks associated with premise plumbing deficiencies in public water systems, (iii) no change in the annual proportion of outbreaks associated with distribution system deficiencies or the use of untreated and improperly treated groundwater in public water systems, and (iv) the increasing importance of Legionella since its inclusion in WBDOSS in 2001. Data from WBDOSS have helped inform public health and regulatory responses. Additional resources for waterborne disease surveillance and outbreak detection are essential to improve our ability to monitor, detect, and prevent waterborne disease in the United States.

Effects of source water quality on chlorine inactivation of adenovirus, coxsackievirus, echovirus, and murine norovirus.

More information is needed on the disinfection efficacy of chlorine for viruses in source water. In this study, chlorine disinfection efficacy was investigated for USEPA Contaminant Candidate List viruses coxsackievirus B5 (CVB5), echovirus 1 (E1), murine norovirus (MNV), and human adenovirus 2 (HAdV2) in one untreated groundwater source and two partially treated surface waters. Disinfection experiments using pH 7 and 8 source water were carried out in duplicate, using 0.2 and 1 mg/liter free chlorine at 5 and 15 degrees C. The efficiency factor Hom (EFH) model was used to calculate disinfectant concentration x contact time (CT) values (mg x min/liter) required to achieve 2-, 3-, and 4-log(10) reductions in viral titers. In all water types, chlorine disinfection was most effective for MNV, with 3-log(10) CT values at 5 degrees C ranging from < or = 0.020 to 0.034. Chlorine disinfection was least effective for CVB5 in all water types, with 3-log(10) CT values at 5 degrees C ranging from 2.3 to 7.9. Overall, disinfection proceeded faster at 15 degrees C and pH 7 for all water types. Inactivation of the study viruses was significantly different between water types, but no single source water had consistently different inactivation rates than another. CT values for CVB5 in one type of source water exceeded the recommended CT values set forth by USEPA's Guidance Manual for Compliance with the Filtration and Disinfection Requirements for Public Water Systems using Surface Water Sources. The results of this study demonstrate that water quality plays a substantial role in the inactivation of viruses and should be considered when developing chlorination plans.

Development and evaluation of porcine cysticercosis QuickELISA in Triturus EIA analyzer.

We evaluated three diagnostic antigens (recombinant GP50, recombinant T24H, and synthetic Ts18var1) for cysticercosis and found that all three performed well in detecting cysticercosis in humans and pigs in several assay formats. These antigens were adapted to a new antibody detection format (QuickELISA). With one single incubation step which involves all reactants except the enzyme substrate, the QuickELISA is particularly suited for automation. We formatted the QuickELISA for the Triturus EIA analyzer for testing large numbers of samples. We found that in QuickELISA formats rGP50 and rT24H have better sensitivity and specificity than sTs18var1 for detecting porcine cysticercosis.

National outbreak of Acanthamoeba keratitis associated with use of a contact lens solution, United States.

An outbreak of Acanthamoeba keratitis, a rare, potentially blinding, corneal infection, was detected in the United States in 2007; cases had been increasing since 2004. A case-control study was conducted to investigate the outbreak. We interviewed 105 case-patients from 30 states and 184 controls matched geographically and by contact lens use. Available contact lenses, cases, solutions, and corneal specimens from case-patients were cultured and tested by molecular methods. In multivariate analyses, case-patients had significantly greater odds of having used Advanced Medical Optics Complete Moisture Plus (AMOCMP) solution (odds ratio 16.9, 95% confidence interval 4.8-59.5). AMOCMP manufacturing lot information was available for 22 case-patients, but none of the lots were identical. Three unopened bottles of AMOCMP tested negative for Acanthamoeba spp. Our findings suggest that the solution was not intrinsically contaminated and that its anti-Acanthamoeba efficacy was likely insufficient. Premarket standardized testing of contact lens solutions for activity against Acanthamoeba spp. is warranted.

A simple method for collecting measured whole blood with quantitative recovery of antibody activities for serological surveys.

Compliance and acceptance for the finger-prick method of blood collection is generally better than for venipuncture. A finger-prick method of blood collection with quantitative antibody recovery is even more important for seroepidemiological surveys. Finger-prick blood collected and dried onto filter paper has been used; but, unfortunately, this method has several disadvantages, including loss of antibody activity, possible contact contamination from blood spots on adjacent filter papers, and difficulties in extracting antibodies, justifying the search for other methods of collecting and transporting blood samples. We report on a simple method of collecting a measured amount of finger-prick blood onto a sample pad, which is immediately transferred to storage/extraction buffer. The diluted blood sample is never dried, and because of the storage buffer, can be transported and stored without refrigeration. Furthermore, the diluted blood samples can then be tested directly without further preparation. We systematically compared several storage/extraction buffers and commercially available filter papers. We showed that antibody recovery was not significantly affected by the type of filter papers used but was significantly affected by the storage/extraction buffer used. The best such buffer is StabilZyme Select.

Enzyme immunoassay of Cryptosporidium-specific immunoglobulin G antibodies to assess longitudinal infection trends in six communities in British Columbia, Canada.

A newly developed enzyme-linked immunosorbent assay (ELISA) that detects immunoglobulin G antibodies to the 27-kDa Cryptosporidium parvum sporozoite surface antigen was used to test 4,097 sera collected from pregnant women in 6 communities in British Columbia, Canada, between January 1996, and December 1997. Waterborne outbreaks of cryptosporidiosis occurred in two of the study communities during the period of follow-up, and ELISA seropositivity was high in all six communities during the study period (77% positive to 92% positive). In the community with the largest outbreak, levels of antibody to the 27-kDa antigen increased rapidly and then decayed to background levels within 3-4 months of the peak of the epidemic curve. Trends in serologic reactivity were complex in all communities, and increased antibody levels not related temporally to known waterborne outbreaks were also observed. Serological assays may provide more accurate information regarding community levels of Cryptosporidium infection.

Malaria chemoprophylaxis and the serologic response to measles and diphtheria-tetanus-whole-cell pertussis vaccines.

BACKGROUND: Acute malaria has been associated with a decreased antibody response to tetanus and diphtheria toxoids, meningococcal, salmonella, and Hib vaccines. Interest in giving malaria drug therapy and prevention at the time of childhood immunizations has increased greatly following recent trials of intermittent preventive therapy during infancy (IPTi), stimulating this re-analysis of unpublished data. The effect of malaria chemoprophylaxis on vaccine response was studied following administration of measles vaccines and diphtheria-tetanus-whole cell pertussis (DTP) vaccines. METHODS: In 1975, six villages divided into two groups of children < or = 74 months of age from Burkina Faso, were assigned to receive amodiaquine hydrochloride chemoprophylaxis (CH+) every two weeks for seven months or no chemoprophylaxis (CH-). After five months, children in each group received either one dose of measles or two doses of DTP vaccines. RESULTS: For recipients of the measles vaccine, the seroconversion rates in CH+ and CH- children, respectively, were 93% and 96% (P > 0.05). The seroresponse rates in CH+ and CH- children respectively, were 73% and 86% for diphtheria (P > 0.05) and 77% and 91% for tetanus toxoid (P > 0.05). In a subset analysis, in which only children who strictly adhered to chemoprophylaxis criteria were included, there were, likewise, no significant differences in seroconversion or seroresponse for measles, diphtheria, or tetanus vaccines (P > 0.05). While analysis for pertussis showed a 43% (CH+) and 67% (CH-) response (P < 0.05), analyses using logistic regression to control for sex, age, chemoprophylaxis, weight-for-height Z-score, and pre-vaccination geometric mean titer (GMT), demonstrated that chemoprophylaxis was not associated with a significantly different conversion rate following DTP and measles vaccines. Seven months of chemoprophylaxis decreased significantly the malaria IFA and ELISA GMTs in the CH+ group. CONCLUSION: Malaria chemoprophylaxis prior to vaccination in malaria endemic settings did not improve or impair immunogenicity of DTP and measles vaccines. This is the first human study to look at the association between malaria chemoprophylaxis and the serologic response to whole-cell pertussis vaccine.

Malaria surveillance--United States, 2001.

PROBLEM/CONDITION: Malaria is caused by any of four species of intraerythrocytic protozoa of the genus Plasmodium (i.e., P. falciparum, P. vivax, P. ovale, or P. malariae). These parasites are transmitted by the bite of an infective female Anopheles sp. mosquito. The majority of malaria infections in the United States occur among persons who have traveled to areas with ongoing transmission. In the United States, cases can occur through exposure to infected blood products, by congenital transmission, or by local mosquitoborne transmission. Malaria surveillance is conducted to identify episodes of local transmission and to guide prevention recommendations for travelers. PERIOD COVERED: This report covers cases with onset of illness in 2001. DESCRIPTION OF SYSTEM: Malaria cases confirmed by blood film are reported to local and state health departments by health-care providers or laboratory staff. Case investigations are conducted by local and state health departments, and reports are transmitted to CDC through the National Malaria Surveillance System (NMSS). Data from NMSS serve as the basis for this report. RESULTS: CDC received reports of 1,383 cases of malaria with an onset of symptoms in 2001 among persons in the United States or one of its territories. This number represents a decrease of 1.4% from the 1,402 cases reported for 2000. P. falciparum, P. vivax, P. malariae, and P. ovale were identified in 50.1%, 27.8%, 4.5%, and 3.6% of cases, respectively. Fourteen patients (1.0% of total) were infected by >/=2 species. The infecting species was unreported or undetermined in 179 (12.9%) cases. Compared with 2000, the number of reported malaria cases acquired in Africa increased by 13.2% (n = 886), whereas the number of cases acquired in Asia (n = 163) and the Americas (n = 240) decreased by 31.5% and 11.4%, respectively. Of 891 U.S. civilians who acquired malaria abroad, 180 (20.2%) reported that they had followed a chemoprophylactic drug regimen recommended by CDC for the area to which they had traveled. Two patients became infected in the United States, one through congenital transmission and one whose infection cannot be linked epidemiologically to secondary cases. Eleven deaths were attributed to malaria, 10 caused by P. falciparum and one caused by P. ovale. INTERPRETATION: The 1.4% decrease in malaria cases in 2001, compared with 2000, resulted primarily from a decrease in cases acquired in Asia and the Americas, but this decrease was offset by an increase in the number of cases acquired in Africa. This decrease probably represents year-to-year variation in malaria cases, but also could have resulted from local changes in disease transmission, decreased travel to malaria-endemic regions, fluctuation in reporting to state and local health departments, or an increased use of effective antimalarial chemoprophylaxis. In the majority of reported cases, U.S. civilians who acquired infection abroad were not on an appropriate chemoprophylaxis regimen for the country in which they acquired malaria. PUBLIC HEALTH ACTIONS: Additional information was obtained concerning the 11 fatal cases and the two infections acquired in the United States. Persons traveling to a malarious area should take one of the recommended chemoprophylaxis regimens appropriate for the region of travel, and travelers should use personal protection measures to prevent mosquito bites. Any person who has been to a malarious area and who subsequently develops a fever or influenza-like symptoms should seek medical care immediately and report their travel history to the clinician; investigation should include a blood-film test for malaria. Malaria infections can be fatal if not diagnosed and treated promptly. Recommendations concerning malaria prevention can be obtained from CDC by calling the Malaria Hotline at 770-488-7788 or by accessing CDC's Internet site at http://www.cdc.gov/travel.

A retrospective examination of the effect of fever and microgametocyte count on mosquito infection on humans infected with Plasmodium vivax.

A retrospective examination was made of archival data collected between 1940 and 1963 on the infection of mosquitoes with the St. Elizabeth strain of Plasmodium vivax. Patients were undergoing malariatherapy for the treatment of neurosyphilis. A total of 845 lots of Anopheles quadrimaculatus mosquitoes were fed during primary infections and 76 during secondary infections. Average percentage infection during the primary infection was 56.55% versus 49.83% during the secondary infection. There appeared to be no relationship between microgametocye density, asexual parasite count, and percentage infection. However, very high fevers appear to have a significant effect on infection rates. Persons with fever > or = 105 degrees F showed the lowest rates of infectivity regardless of parasitemia; persons with moderate (101-104.8 degrees F) fever produced somewhat higher rates, and persons with no fever had the highest levels of infection at all parasitemia levels greater than 1,500/microL

A retrospective examination of reinfection of humans with Plasmodium vivax.

A retrospective examination was made of archival data collected between 1940 and 1963 to determine the impact of reinfection of patients with Plasmodium vivax with homologous and heterologous strains of the parasite. Following reinfection of 14 patients with a homologous strain, the geometric mean maximum parasite count was reduced from 9,101/microL during the primary infection to 998/microL and the geometric mean daily parasite count for the first 20 days was reduced from 923/microL to 16/microL. Following reinfection of 22 patients with heterologous strains of P. vivax, the geometric mean maximum parasite count was 8,460/microL during the primary infection versus a secondary level of 9,196/microL and the geometric mean daily parasite count decreased from 847/microL/day to 335/microL/day. Reductions in fever episodes > or =101 degrees F and > or = 104 degrees F appeared to be a more sensitive measure of clinical immunity. Fever episodes > or =104 degrees F in patients with homologous strain reinfections decreased from 1.92 episodes per week to 0.18 compared with 1.24 to 0.57 in patients with heterologous infections. Fever episodes > or =101 degrees F decreased from 2.98 to 0.60 in the homologous strain compared with 2.08 to 1.07 for the heterologous infections. The average maximum fever temperature in the homologous group was 106 degrees F during the primary infection versus 103.4 degrees F for the secondary infection compared with 105.8 degrees F during the primary infections versus 105.6 degrees F for the secondary infection in the heterologous patients.

A retrospective examination of anemia during infection of humans with Plasmodium vivax.

A retrospective examination was made of archival data on 98 patient episodes of infection with Plasmodium vivax occurring over a period of 4-11 weeks to document changes in hemoglobin (Hb) concentrations associated with continuing parasitemia. The mean percentage change in the Hb concentration for each of the 10 seven-day intervals was -13.4, -10.9, -4.8, 0.12, 0.94, 4.0, 0.69, 11.6, 2.4, and 8.3, respectively. An equilibrium appeared to be established between weeks 4 and 6. Decreases in Hb concentrations were greatest following the first week of parasitemia. Total restoration to preinfection levels did not occur during persistent parasitemia.

Porcine antibody responses to taenia solium antigens rGp50 and sTs18var1.

Cysticercosis, a disease caused by the larval form of Taenia solium, is diagnosed by detection of specific antibodies or by imaging techniques. Our preferred immunologic assay for cysticercosis is the enzyme-linked immunoelectrodifusion transfer blot, or immunoblot, using the lentil lectin bound antigens from larval cysts. Antibody reactivity with any one of seven glycoproteins is diagnostic for cysticercosis. To develop a simple antibody detection assay for field use, we have synthesized an 8-kD diagnostic antigen, sTs18var1 (a secreted protein with a mature size of 67 amino acids), and expressed a 50-kD membrane protein antigen, rGp50. We used these two diagnostic proteins in a quantitative Falcon assay screening test-enzyme-linked immunosorbent assay (FAST-ELISA) to measure the antibody responses in Peruvian pigs with cysticercosis. Three study designs were used. First, we followed the kinetics of antibody responses against these two diagnostic proteins in pigs with cysticercosis that were treated with oxfendazole. Second, we measured antibody response in naive experimentally infected pigs. Third, we followed the maternal antibodies against rGp50 and sTs18var1 in piglets born from sows with cysticercosis. These studies showed that antibody responses against the two diagnostic proteins in the FAST-ELISA are quantitatively correlated with infection by viable cysts, with anti-sTs18var1 activity being most responsive to the status of infection.

Reactivity to bacterial, fungal, and parasite antigens in patients with lymphedema and elephantiasis.

Both secondary infections and antifilarial immunity are thought to play roles in the development and progression of lymphedema. To investigate this issue, immune responses to a panel of bacterial, fungal, and parasite antigens were examined for women with lymphedema and elephantiasis (n = 28) and for women with no clinical evidence of lymphatic dysfunction who were either microfilaremic (Mf+, n = 23) or microfilaria- and filarial antigen-negative (Ag-, n = 24). The prevalence and intensity of delayed-type hypersensitivity (DTH) responses was similar for most recall antigens; for individual antigens, lymphedema patients were significantly more likely to be reactive only to Proteus. Lymphedema patients with a history of three or more attacks of adenolymphangitis in the last 18 months showed increased DTH reactivity to Trichophyton. Proliferative responses to fungal and bacterial antigens were similar for all three groups; however, antigen-negative women, independent of disease status, mounted greater responses to filarial antigen. In contrast, lymphedema patients had higher levels of antifilarial specific IgG1, IgG2, and IgG3 and higher IgG responses to streptolysin O than either Ag- or Mf+ women. In persons with lymphatic filariasis, immune reactivity is influenced by disease status as well as infection status.

Community-wide reduction in prevalence and intensity of intestinal helminths as a collateral benefit of lymphatic filariasis elimination programs.

Annual mass treatment with antifilarial drugs is the cornerstone of the global program to eliminate lymphatic filariasis (LF). Although the primary goal of the program is to interrupt transmission of LF, additional public health benefits also are expected because of the known anthelminthic properties of these drugs. Since rapid re-infection with intestinal helminths occurs following treatment, annual de-worming may not be sufficient to produce a lasting reduction in the prevalence and intensity of these infections. We conducted stool examinations in four sentinel communities before and approximately nine months after each of two rounds of mass drug administration (MDA) with diethylcarbamazine and albendazole in the context of an LF elimination program in Leogane, Haiti. At baseline, overall Ascaris, Trichuris, and hookworm infection prevalences were 20.9%, 34.0%, and 11.2%, respectively (n = 2,716 stools). Nine months after the second MDA, Ascaris, Trichuris and hookworm prevalences had decreased significantly, to 14.1%, 14.6%, and 2.0%, respectively (n = 814 stools). Infection intensity decreased significantly for all three parasites as well. These results demonstrate that substantial reductions in intestinal helminth infections are associated with mass treatment of filariasis in Haiti and are consistent with the conclusion that high levels of coverage for the LF program can decrease transmission of geohelminths.

Care seeking behaviour and treatment of febrile illness in children aged less than five years: a household survey in Blantyre District, Malawi.

Malaria is a leading cause of death in children aged < 5 years in Malawi. As part of the Roll Back Malaria initiative, African heads of state have pledged that by 2005, 60% of children will receive an effective antimalarial drug within 24 h of developing fever. In 1993, Malawi switched from chloroquine to sulfadoxine-pyrimethamine (SP) in its recommendations of home treatment of febrile illness in children. To study care seeking behaviour and home treatment in Blantyre District, and provide valuable follow-up to the chloroquine to SP transition, we performed a 2-stage cluster-sample survey in February 2000. Our sample of 1080 households included 672 households with children aged < 5 years; 292 (32.2%, 95% CI 28.7-35.8%) of the 912 children in these households had completed a febrile episode within the past 14 d. Among recently febrile children, 210 (72.0%, 95% CI 67.0-77.1%) received medication at home during their illness, but only 36 (12.2%, 95% CI 8.4-16.0%) received an appropriate antimalarial drug. Overall, 111 (37.4%, 95% CI 30.9-43.9%) received prompt, appropriate treatment. Only rural location was statistically associated with failure to receive prompt appropriate treatment (risk ratio estimate 1.2, 95% CI 1.01-1.5). A greater effort to improve the quality of malaria home treatment or to expand health facility utilization will be necessary to achieve Roll Back Malaria goals before 2005 in Blantyre District. Current care seeking practices suggest interventions should stress promptness of health facility visits, improved access to appropriate drugs, and accurate dosing for home-based treatments.

PCR and Mosquito dissection as tools to monitor filarial infection levels following mass treatment.

BACKGROUND: Entomological methods may provide important tools for monitoring the progress of lymphatic filariasis elimination programs. In this study, we compared dissection of the vector, Culex quinquefasciatus, with the polymerase chain reaction (PCR) to assess filarial infection levels in mosquitoes in the context of a lymphatic filariasis elimination program in Leogane, Haiti. METHODS: Mosquitoes were collected using gravid traps located in 4 sentinel communities with Wuchereria bancrofti microfilaria prevalence that ranged from 0.8% to 15.9%. Captured mosquitoes were divided between dissection, to enumerate W. bancrofti larvae (L1, L2, L3) and desiccation for later analysis by PCR. PCR was conducted on DNA extracts from pooled mosquitoes (1-15 pooled females) utilizing a competitive PCR system with primers specific for the Ssp I repeat. PCR products were analyzed with a hybridization ELISA using probes specific for a control sequence and the Ssp I repeat. RESULTS: The prevalence of mosquito infection with W. bancrofti ranged from 0%-3.66% by dissection (L1-L3) and point estimates of infection prevalence, as assayed by PCR, ranged from 0.25% - 9.16%. Following mass treatment, W. bancrofti infection prevalence dropped significantly as determined by PCR and dissection in 2 of the 4 sentinel sites (Leogane and Barrier Jeudi, P = 0.04 and P = 0.005, respectively). Although transmission declined in the other two sites, larval recoveries were low and these changes were not statistically significant. DISCUSSION: Our results suggest that a single round of mass treatment can have an impact on transmission of lymphatic filariasis. The use of entomologic methods as a tool to monitor filariasis programs and the statistical limitations of mosquito trapping are discussed.

Changes in Hematologic Values During Infection of New World Monkeys With Plasmodium falciparum and P. vivax.

Owl (Aotus sp.) and squirrel (Saimiri sp.) monkeys are used frequently in malaria vaccine trials, during which the animals are monitored daily for parasitemia and general well-being. Every 2 weeks, blood samples are taken, and hematology and chemistries are performed. We examined 97 cases of malarial infection in owl and squirrel monkeys, whose parasitemia increased by. 22,000 parasites/uL daily during a 14-day interval. After malaria challenge, unprotected animals had significant changes in hematologic values. These changes could not be completely attributed to the increase in the parasite counts.

Source water quality effects on monochloramine inactivation of adenovirus, coxsackievirus, echovirus, and murine norovirus.

There is a need for more information regarding monochloramine disinfection efficacy for viruses in water. In this study, monochloramine disinfection efficacy was investigated for coxsackievirus B5 (CVB5), echovirus 11 (E11), murine norovirus (MNV), and human adenovirus 2 (HAdV2) in one untreated ground water and two partially treated surface waters. Duplicate disinfection experiments were completed at pH 7 and 8 in source water at concentrations of 1 and 3 mg/L monochloramine at 5 and 15 °C. The Efficiency Factor Hom (EFH) model was used to calculate CT values (mg-min/L) required to achieve 2-, 3-, and 4-log(10) reductions in viral titers. In all water types, monochloramine disinfection was most effective for MNV, with 3-log(10) CT values at 5 °C ranging from 27 to 110. Monochloramine disinfection was least effective for HAdV2 and E11, depending on water type, with 3-log(10) CT values at 5 °C ranging from 1200 to 3300 and 810 to 2300, respectively. Overall, disinfection proceeded faster at 15 °C and pH 7 for all water types. Inactivation of the study viruses was significantly different between water types, but there was no indication that overall disinfection efficacy was enhanced or inhibited in any one water type. CT values for HAdV2 in two types of source water exceeded federal CT value recommendations in the US. The results of this study demonstrate that water quality impacts the inactivation of viruses and should be considered when developing chloramination plans.