The American Journal of Tropical Medicine and Hygiene - Volume 75, Issue 6, December 2006

The effects of HIV co-infection and multi-drug resistant tuberculosis (MDRTB) on tuberculosis prognosis are poorly defined. Therefore, we studied infectiousness and mortality of 287 tuberculosis patients treated with standard, directly observed, short-course therapy in the Peruvian community. During 6–17 months of treatment, 49 (18%) of patients died, of whom 48 (98%) had AIDS and 28 (57%) had MDRTB; 17/31 (55%) of MDRTB-patients with AIDS died within 2 months of diagnosis, before traditional susceptibility testing would have identified their MDRTB. Most non-MDRTB became smear- and culture-negative within 6 weeks of therapy, whereas most MDRTB remained sputum-culture-positive until death or treatment completion. HIV-negative patients with non-MDRTB had good outcomes. However, MDRTB was associated with prolonged infectiousness and HIV co-infection with early mortality, indicating a need for greater access to anti-retroviral therapy. Furthermore, early and rapid tuberculosis drug-susceptibility testing and infection control are required so that MDRTB can be appropriately treated early enough to reduce mortality and transmission.

As part of an extensive study of the eco-epidemiology of urinary schistosomiasis along the southern coast of Kenya, spatial and temporal transmission patterns were associated with various ponds infested with Bulinus snails. The household-level spatial pattern of infection for children of various age groups in 2000 was contrasted with historical data from 1984. Significant local clustering of high and low infection levels among school age children was detected, and the spatial extent of clusters and their direction from specific water sources were measured. High infection levels were clustered around ponds known to contain Bulinus nasutus snails that shed Schistosoma haematobium cercariae, and low infection levels were concentrated near a river where intermediate host snails were rarely found. The spatial patterns of infection varied between 2000 and 1984 and between age groups. High levels of infection were clustered around different transmission foci in the two study periods, and, for younger children in 2000, were clustered nearer to the transmission foci than for the older children. Simultaneous consideration of the effects of different foci on transmission will allow for targeted application of control measures aimed at interrupting S. haematobium transmission at a local level.

We assessed morbidity indicators for both Schistosoma haematobium and Schistosoma mansoni infections and evaluated the appropriateness of the World Health Organization (WHO) guidelines for ultrasound in schistosomiasis in the context of large-scale control interventions. Abdominal and urinary tract ultrasonography was performed on 2,247 and 2,822 school children, respectively, from 29 randomly selected schools in Mali before the implementation of mass anthelminthic drug administration. Using two-level logistic regression models, we examined associations of potential factors with the risk of having a positive ultrasound global score (morbidity indicative of S. haematobium infection), abnormal image pattern scores, dilatation of the portal vein, and/or enlarged liver (morbidity indicative of S. mansoni infection). The WHO protocol was found useful for detection of S. haematobium pathology but overestimated the risk of portal vein dilatation and left liver lobe enlargement associated with S. mansoni infection. We conclude that ultrasonography should be included in large-scale control interventions, where logistics allow, but cautiously.

A high level of serum IgE is generally associated with human resistance to schistosomes, though the protective mechanisms of IgE remain undefined. We recently reported that whereas some individuals who are occupationally hyperexposed to Schistosoma mansoni display resistance to reinfection, others remain highly susceptible, in some cases due to HIV-1 co-infection. As IgE functions, in part, through FcεRI on mast cells, we characterized circulating CD117+ FcεRI+ mast cell precursors in this population. Surprisingly, a higher percentage of CD117+ cells correlated with a susceptible phenotype in HIV-1 seronegative participants with schistosomiasis. There was no association between percentages of peripheral CD117+ cells and susceptibility to reinfection in persons with HIV-1. Serum levels of polyclonal IgE were inversely correlated with percentages of CD117+ cells regardless of HIV-1 status. Thus, immature mast cells may affect IgE availability, or IgE may affect immature mast cells, altering the balance of host susceptibility and resistance to schistosomes.

World Health Organization certification criteria for onchocerciasis elimination use anterior segment eye lesion prevalence as an indicator of mass ivermectin treatment program success. Lesions either contain visible microfilaria (noninflammatory punctate keratitis [PK] or microfilariae in anterior chamber [MFAC]), or microfilaria obscured by inflammation (inflammatory PK). To assess the utility of these disease indicators, two experienced ophthalmologists independently examined persons from endemic (N = 325) and nonendemic (N = 348) Guatemalan communities. Thirty-six (11.1%) and nine (2.6%) persons from endemic and nonendemic areas respectively had lesions found by either ophthalmologist (prevalence ratio = 4.3, 95% CI 2.1–8.8, P < 0.001). All lesions in nonendemic areas were inflammatory PK in whom no persons were seropositive for onchocerciasis. Overall, observer agreement was moderate (Kappa = 0.49), and most (61%) discordance occurred with inflammatory PK lesions. Our findings suggest that inflammatory punctate keratitis is neither a specific nor a reliable indicator of onchocercal eye disease. Future prevalence surveys should rely upon noninflammatory lesions as disease indicators.

This article presents an evaluation of the community perception of the recently implemented School Based Health Program, which delivered anthelmintics to 96,000 schoolchildren in Sanliurfa, Turkey. One hundred forty-four parents and 140 teachers were interviewed through questionnaires, focus group discussions, and in-depth interviews. The evaluation indicated that most of the parents and teachers reported that the program was beneficial as it led to improvement in children’s health and well being. The evaluation also indicated that 99% of the parents and 98.4% of the teachers approved of the teacher’s role in this program. Nearly all of the teachers and parents showed willingness to continue the program in the future and 75% of the parents indicated willingness to pay for the drugs. The evaluation also highlighted that there were critical issues for the successful implementation of the program such as the issue of educating illiterate mothers, higher involvement of families in the mass treatment process, ability to reach a larger number of school absentees, and overcoming the prejudice against externally funded measures, which are perceived by some of the members of the community as an experiment run by foreigners on the local population and the concern of some parents that anthelmintic drug (mebendazole) might cause sexual sterility.

Three of thirteen Oryzomys acritus, Emmons and Patton 2005 (Rodentia: Muridae: Sigmodontinae) and 3 of 17 Oryzomys nitidus, Thomas 1884, collected from Noël Kempff National Park, Bolivia, from 2002 to 2005, tested positive for Leishmania (Leishmania) amazonensis or L. (L.) mexicana and negative for Leishmania (Viannia) spp. using the polymerase chain reaction (PCR). Based on previous records of L. (L.) amazonensis in humans, rodents, and sand flies from Bolivia, and the geographic distributions of L. (L.) amazonensis and L. (L.) mexicana, it was concluded that the Oryzomys were infected with L. (L.) amazonensis. These results identify two additional species of Oryzomys as hosts of L. (L.) amazonensis, and identify an ecological region of Bolivia where L. (L.) amazonensis is enzootic.

A 35-year-old man with a 19-year history of slowly evolving diffuse cutaneous leishmaniasis was treated with oral miltefosine, 50 mg three times a day. The patient responded after four months of miltefosine treatment with clearance of all nodular lesions and plaques from the entire body surface and had negative slit-skin smears and cultures for Leishmania. However, two months after stopping miltefosine, skin lesions reappeared and parasites were observed in samples. The relapsed lesions did not respond to an additional two-month course of miltefosine. No laboratory or clinical adverse events to miltefosine were observed. Parasites from skin lesions were cultured and identified as Leishmania (Leishmania) mexicana by isoenzyme electrophoresis.

Here we report a documented case of congenital transmission of Trypanosoma cruzi from a Bolivian mother with chronic Chagas disease living in Spain. The serology and blood nested polymerase chain reaction (PCR) were positive for the mother, and amastigote forms were observed in histopathological study of the placenta and umbilical cord. Direct examination, culture, and nested PCR were positive in the blood of the neonate. At the age of 8 days, the neonate began treatment with 5–7.5 mg/kg/day of benznidazol, which was continued for 60 days. Direct examination, blood culture, and nested PCR were negative to T. cruzi 20 days after the start of treatment and remained negative 4 and 7 months thereafter. Serological tests were negative at 4 months. To detect congenital infection and initiate early treatment of infected newborns, protocols are required to detect Chagas disease in pregnant women who migrate from endemic to non-endemic areas.

Although Trypanosoma cruzi can be transmitted transplacentally and induce congenital infection, no data are available about the presence of this parasite in human amniotic fluid. We examined 8, 19, and 4 amniotic fluid samples (collected at delivery or by aspiration of gastric content of neonates) from control uninfected mothers (M−B−), infected mothers delivering uninfected newborns (M+B−), and mothers of confirmed congenital cases (M+B+), respectively. Polymerase chain reaction (PCR), using nuclear and kinetoplastic DNA primers (Tcz1-Tcz2 and 121–122), were negative for all control M−B− samples, but positive for 5 of 19 M+B− and 2 of 4 M+B+ samples. To determine the number of parasites in the positive samples, real-time PCR using S35/S36 kinetoplastic DNA was performed. Only one M+B+ sample presented a high parasitic DNA amount, whereas the other six PCR-positive samples displayed traces of T. cruzi DNA. In conclusion, the release of parasites in amniotic fluid is probably a rare event that cannot be helpful for the routine diagnosis of congenital Chagas disease.

The epidemiologic status of leptospirosis in Egypt has not been well defined because of difficulties in disease diagnosis. A retrospective study was conducted to detect leptospiral antibodies among undiagnosed acute febrile illness (AFI) and hepatitis cases. Approximately 16% of both AFI (141/886) and acute hepatitis (63/392) cases showed seroreactivity to Leptospira IgM by ELISA and microscopic agglutination test (MAT). Canicola, Djasiman, Grippotyphosa, Pyrogenes, Icterohemorrhagiae, and Pomona were the most commonly reactive serovars among patients with AFI. Djasiman, Grippotyphosa and Icterohemorrhagiae were the most reactive among patients with acute hepatitis. This study represents the first systematic report of Leptospira associated with patients with AFI and hepatitis in Egypt. Physicians need to have increased awareness about the importance of leptospirosis in the differential diagnosis of AFI and acute hepatitis in Egypt. In addition, laboratory capacity should be developed at fever hospitals to diagnose leptospirosis.

To determine whether recurrent episodes of appropriately treated Lyme disease are caused by reinfection or relapse, we monitored pertinent clinical manifestations and serology of residents of an endemic site each year for 14 years. Of 253 episodes of early Lyme disease recorded among 213 residents, we observed 40 recurrent episodes. Virtually all included an erythema migrans (EM) rash that appeared at body sites that differed from those of the initial rash, no subjects produced detectable levels of specific antibody between sequential episodes, all episodes occurred a year or more after the initial EM episode, and all occurred during late spring and early summer. People experiencing recurrent episodes tended to have frequent contact with vector ticks. Prompt administration of standard antibiotic therapy for early Lyme disease reliably eliminates persistent infection and prevents relapse.

Parasitic diseases are very important in Mexico because of their economic impact and adverse effects on normal growth in children. Cryptosporidiosis has been associated with acute diarrhea in immune competent and incompetent human hosts, fecal contamination of drinking water sources, and handling of animals. Due to the lack of reports on cryptosporidiosis in Mexico, we conducted a parasitologic study in children with diarrhea and other clinical symptoms. The main objectives were 1) to determine the prevalence of cryptosporidiosis in children less than one year of age in Mexico City, and 2) to correlate Cryptosporidium infection with gastrointestinal symptoms. Two hundred fecal samples from children seen at the Gabriel Mancera Familiar Medicine Unit of the Instituto Mexicano del Seguro Social were studied. Children were divided into two groups. Group A was composed of sick children with 6–8 watery diarrheic episodes every 24 hours attended at the emergency service. Group B was composed of healthy babies getting routine check ups. Only children in group A were found to be infected with intestinal protozoa (50% with Giardia lamblia, 41% with Cryptosporidium spp., and 4% with Entamoeba histolytica). The results suggested a high incidence of Cyrptosporidium infections in children in Mexico City, which make these observations useful for future studies.

The aim of this study was to evaluate the use of polymerase chain reaction (PCR) amplification of the O. tsutsugamushi 16S rRNA gene for the diagnosis of scrub typhus in rural Thailand. A prospective study of acute febrile illness in Udon Thani, northeast Thailand, identified 183 patients as having scrub typhus on the basis of immunofluorescent antibody testing (IFA) of paired sera. A further 366 febrile patients admitted concurrently with a range of other diagnoses acted as negative controls. Diagnostic sensitivity and specificity of 16S rRNA PCR was 44.8% and 99.7%, respectively, compared with IFA. PCR positivity was related to duration of symptoms and presence of eschar (P < 0.001, both cases). PCR using primers to amplify a fragment of the 56-kd gene had a sensitivity and specificity of 29.0% and 99.2%, respectively. PCR has a high specificity but low sensitivity for the rapid diagnosis of scrub typhus in this endemic setting.

Methods for early diagnosis of pediatric HIV-1 infection (DNA-polymerase chain reaction [PCR], RNA quantification, viral cultures) are expensive. Most Cambodian infants wait 18 months for HIV serologic tests. We observed that boosted-p24-antigen profile assay, with performances similar to viral cultures and costs similar to DNA-PCR, is easier to perform and could readily be set up in resource-poor settings.

Fungal mycetoma (or eumycetoma) are endemic diseases in tropical areas that have economic effects because of their chronic and disabling evolution. Classic treatments include surgery and antifungal drugs, but these have multiple side effects. We report a case of black-grain fungal mycetoma successfully treated with voriconazole without side effects. The duration of the treatment remains unclear, but must be prolonged because of the frequency of relapses.

Treatment with amphotericin B deoxycholate (AB) is associated with dose-related nephrotoxicity. We conducted an open and randomized trial to evaluate the efficacy of an oral rehydration solution (ORS) to prevent nephrotoxicity of AB, compared with an intravenous saline solution (SS). Adult patients with mucosal leishmaniasis in whom AB was indicated received either three liters or ORS or one liter of SS. Renal function tests were performed at baseline and during treatment. Forty-eight patients were included (ORS = 25, SS = 23). No difference was observed in serum creatinine, creatinine clearance, serum urea, and serum sodium values during treatment, but serum potassium values were lower in the SS group than in the ORS group (P < 0.03). Treatment was more temporarily discontinued in the SS group than in the ORS group (7 patients versus 1 patient, P = 0.02). We conclude that ORS is comparable to SS in preventing glomerular damage of AB, but more effective in preventing hypokalemia.

A dengue epidemic caused by dengue virus 3 (DENV-3) occurred in Cuba in 2001–2002. It included cases of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS). We report neutralizing antibody studies on sera from 54 of 78 DHF/DSS patients that provide evidence of infections occurring in the sequence DENV-1 followed by DENV-3. No sera showed infection in the sequence DENV-2 followed by DENV-3. Some sera showed a pattern of infection in the sequence DENV-1 followed by DENV-2 and then DENV-3. However definitive categorization of a tertiary infection was not possible because of broadly reactive antibodies, which could have been raised by infections in the sequence DENV-1 then DENV-3.

When Aedes albopictus larvae were infected with C6/36 densovirus (C6/36DNV), the mortality reached 97.46% within 21 days for those larvae infected at the first day after hatching, and 14.17% for control. A real-time quantitative polymerase chain reaction (qPCR) was used to trace the dynamic change of the quantity of C6/36DNV genomes in the larvae and the adults, and to study the interaction of C6/36DNV with dengue virus type II(DEN-II) in mosquitoes. It showed that C6/36DNV could persist in the adults that could transmit C6/36DNV vertically to the next generation. The quantity of C6/36DNV after DEN-II infection increased by 102~103 times in the C6/36DNV-positive mosquitoes, and the quantity of DEN-II in the C6/36DNV-positive mosquitoes was about 100 times lower than that in the C6/36DNV-negative mosquitoes, which suggested that DEN-II could remarkably stimulate the reproduction of C6/36DNV, while C6/36DNV persisted in mosquitoes could inhibit the reproduction of DEN-II. The study throws light on C6/36DNV as a possible biologic control agent against dengue virus and Ae. albopictus.