The American Journal of Tropical Medicine and Hygiene - Volume 77, Issue 5, November 2007

We undertook active population-based surveillance in 5,000 urban households among children < 5 years old to determine invasive pneumococcal disease (IPD) incidence, serotype distribution, clinical presentation, and antimicrobial resistance, which have not been previously described in population-based studies from the region. IPD was documented by blood culture isolation. From 01 April 2004 to 31 March 2006, 5,903 blood cultures were collected from 6,167 eligible children. Streptococcus pneumoniae was isolated from 34 pneumococcal patients; IPD was clinically associated with pneumonia (24%), upper respiratory infection (62%), and febrile syndromes (14%). Overall, IPD and 13-valent serotype–related IPD incidences were 447 and 276 episodes/100,000 child-years, respectively. Peak IPD incidence occurred during the cool dry seasons. Penicillin, cotrimoxazole, chloramphenicol, and ciprofloxacin resistances were 2.9%, 82.4%, 14.7%, and 24.1%, respectively. Current conjugate vaccines should substantially reduce IPD, childhood pneumonia, and antimicrobial resistance in Bangladesh.

The prevalence, incidence, and epidemiologic factors of Clostridium difficile–associated diarrhea (CDAD) in a Peruvian hospital were studied. We conducted a cross-sectional study in patients > 14 years of age from medical/surgical wards of the Cayetano Heredia National Hospital (Lima, Peru) from September 2005 to May 2006. CDAD was defined in a case of nosocomial diarrhea when C. difficile toxin A and/or toxin B was detected by enzyme immune assay (EIA) in stools. A total of 4,264 patients were admitted, with 156 (3.7%) developing nosocomial diarrhea. Fifty-five of 156 (35.2%) cases of nosocomial diarrhea were diagnosed as CDAD. The overall incidence per 1,000 admissions was 12.9. Multivariate analysis showed that use of diapers (OR, 3.54; 95% CI, 1.71–7.34; P = 0.001) and presence of another patient with CDAD housed in the same room (OR, 2.97; 95% CI, 1.14–7.76; P = 0.026) were significantly associated with CDAD. Hospital transmission of C. difficile commonly occurred, supporting infection-appropriate measures directed toward the reduction of CDAD in low-resource settings.

More cutaneous anthrax cases were noted at Hospital Albert Schweitzer (HAS) in the Artibonite Valley of Haiti. We examine the incidence of anthrax in the Artibonite between 1992 and 2002, describe the clinical presentation of cutaneous anthrax, and determine risk factors for anthrax. In 1992 HAS reported 1 case of anthrax for an incidence of 4 cases per million persons/year. In 2002, there were 20 cases of anthrax for an incidence of 72 cases per million persons/year. This is a 17-fold increase (P = 0.0002). Causes of death from anthrax included asphyxiation from edema of the neck with tracheal compression and concurrent gastrointestinal anthrax. Butchering cattle that had died of illness was identified as a risk factor. The incidence of human anthrax has increased in the Artibonite Valley and is a cause of significant mortality. Control of anthrax in humans depends on improved animal vaccination programs.

We undertook a prospective study to quantitate Burkholderia pseudomallei in blood, pus, respiratory secretions, and urine obtained from 414 patients with melioidosis. The median was count 1.1, 1.5 × 104, 1.1 × 105, and 1.1 × 107 CFU/mL in these sample types, respectively. This provides important insights into the likely feasibility of future studies such as expression microarray analysis using clinical material.

The accuracy of a Burkholderia pseudomallei 16s rRNA real-time PCR assay was evaluated against culture for the diagnosis of melioidosis in Thailand. A total of 846 samples were obtained from 383 patients with suspected melioidosis. One or more specimens were PCR positive for 47 of 77 patients with culture-proven melioidosis (sensitivity 61.0%, 95% CI: 49.2–72.0%). PCR was negative for all 306 patients who were culture negative for B. pseudomallei (specificity 100%, 95% CI: 98.8–100%). Diagnostic sensitivity of PCR was 22.7% for patients who were culture positive for blood only, compared with 79.4% for patients who were culture positive for samples other than blood. The median (interquartile range) B. pseudomallei colony count in blood for 44 of 77 patients with positive blood cultures was 2.4 CFU/ml (0.2–13.5 CFU/ml); this may explain the low sensitivity of PCR for this specimen. The PCR assay described here is not sufficiently sensitive to replace culture in our clinical setting.

Infections from Cryptosporidium parvum are of interest not only to public health, but also to wildlife conservation, particularly when humans and livestock encroach on nature and thereby increase the risk of cross-species transmissions. To clarify this risk, we used polymerase chain reaction to examine the hypervariable region of the C. parvum 18S rRNA gene in feces from three monkey species. Samples were isolated from regions where disease transmission between monkeys, livestock, and humans was likely (soiled habitat) or unlikely (clean habitat). Monkey individuals, their social groups, and different species shared multiple genotypes/isolates of C. parvum. Ecological and molecular analyses suggested that Cryptosporidium infection among Toque macaques in soiled habitats was mainly the bovine genotype C. parvum. Monkeys inhabiting clean habitat, particularly gray and purple-faced langurs, lacked Cryptosporidium species/types associated with bovines. Livestock apparently was a main source of infection for wild primates.

We investigated 245 diarrheal stool specimens from HIV-positive subjects between January 2003 and December 2006 to determine the etiological role of coproparasites. Parasitic etiology was observed in 91 (37.1%) cases. Isospora belli (26.1%) was the most common parasite followed by Entameba histolytica/dispar (3.3%), Cryptosporidium spp. (2.9%), Giardia intestinalis (1.6%), and Strongyloides stercoralis (1.2%). Interesting trends of significant increase in the number of cases of I. belli and decline in Cryptosporidium spp. were observed during the study period.

Seroprevalence of Entamoeba histolytica infection in HIV-infected individuals from Shanghai city, Anhui province, and Henan province, China, was examined by enzyme-linked immunosorbent assay using crude antigen and a recombinant surface antigen, C-Igl, of the parasite. In 215 HIV-infected individuals, the positive rates for these antigens were 12.1% and 7.9%, respectively; these rates were significantly higher than the rates of 3.1% and 0.5%, respectively, in 191 patients with gastrointestinal symptoms who were not infected with HIV. There was no significant difference in seropositivity to E. histolytica between men and women. Seropositivity in HIV-infected individuals was higher in patients with a CD4+ T cell count of < 200/μL. This is the first report showing a higher seroprevalence of E. histolytica infection in HIV-infected patients in China. Our results also suggest that HIV infection is a risk factor for infection with E. histolytica.

Leprosy affects skin and peripheral nerves, and acute inflammatory type 1 reactions (reversal reaction) can cause neurologic impairment and disabilities. Single skin lesion paucibacillary leprosy volunteers (N = 135) recruited in three Brazilian endemic regions, treated with single-dose rifampin, ofloxacin, and minocycline (ROM), were monitored for 3 years. Poor outcome was defined as type 1 reactions with or without neuritis. IgM anti-phenolic glycolipid I, histopathology, Mitsuda test, and Mycobacterium leprae DNA polymerase chain reaction (ML-PCR) were performed at baseline. χ2 test, Kaplan-Meir curves, and Cox proportional hazards were applied. The majority of volunteers were adults with a mean age of 30.5 ± 15.4 years; 44.4% were ML-PCR positive. During follow-up, 14.8% of the patients had a poor clinical outcome, classified as a type 1 reaction. Older age (≥40 years), ML-PCR positivity, and lesion size > 5cm were associated with increased risk. In multivariate analysis, age (≥40 years) and ML-PCR positivity remained baseline predictors of type 1 reaction among monolesion leprosy patients.

We conducted a case-control study to investigate the association between Buruli ulcer (BU) and environmental- and health-related behaviors in southern Benin. Hospital BU cases (N = 324) and sex- and age-matched neighborhood controls (N = 1,173) answered a questionnaire. Regular use of soap for washing, treating injuries with soap or antibiotic powder, and frequent contact with flowing water appeared protective against BU.

Two TaqMan-based real-time polymerase chain reaction (PCR) assays devised for the detection of two bovine Babesia parasites, Babesia bovis and B. bigemina, were evaluated for their diagnostic utility using cultured parasites and 92 field bovine blood samples collected from cattle living in Brazil. The real-time PCR assays were compared with previously established nested-PCR assays. The detection limits of both B. bovis- and B. bigemina–real-time PCR assays were identical at the value of 2.5 parasites/μL of the infected blood. When 92 field bovine blood samples were tested using the real-time assays, B. bovis-positive signals were observed in 30 samples among 31 B. bovis-positive blood samples in the nested-PCR assay (96.9% sensitivity and 100% specificity), whereas the B. bigemina–real-time PCR assay could detect the parasite from all of 45 B. bigemina-positive blood samples in the nested-PCR assay (100% sensitivity and specificity). The real-time assays using the TaqMan-system can therefore be practically implemented in the epidemiologic survey for bovine babesiosis. Further studies will be necessary to investigate the clinical value of this technique, especially for the quantitative detections of the parasites.

Ciguatera is a tropical disease caused by seafood poisoning, for which the duration of symptoms remains to be determined. The objectives of this prospective study were to determine the prevalence of symptoms at different time points and to identify factors associated with chronic symptoms observed in adults suffering from this disease. At the time of onset, we observed a dose–response relationship including a strong association between the delay of appearance of symptoms and a severity index (P < 0.001). Our results confirmed the key role of fish organs in the risk of contracting a more severe form of ciguatera. In the chronic stage, only the severity score based on information recorded in the acute phase is related to the persistence of symptoms (P < 0.001). Our findings suggest that several symptoms observed in the acute phase of the disease are still experienced 15 days after onset. This supports previous observations based on isolated case reports.

Snake envenoming in pregnancy may cause fetal death and maternal mortality or morbidity. However, little is known about the toxic effects and optimal management of snake envenoming because of the rarity of cases. We report three cases in Taiwan in the past 15 years of pregnant women who were treated successfully after being bitten by Trimeresurus stejnegeri with local envenoming. Two of the three patients received treatment with equine-derived hemotoxic bivalent F(ab′)2 antivenom without development of any adverse effects. All three women recovered uneventfully and subsequently had normal deliveries. Telephone follow-up of the three children 6–10 years later showed no developmental delay of the children.

We describe two patients who developed severe illness after eating the skin and eggs of a toad, probably Bufo melanostictus Schneider, in southeastern Laos. One boy died, and one developed a digoxin toxicity–like syndrome with bradycardia and heart failure but survived. A telephone survey of 16 Lao provincial hospitals suggested that toad poisoning occurs in at least six provinces. That 93% of villagers in three villages in southeastern Laos were aware that toads are poisonous but that 51% had encountered patients with toad toxicity suggests that the potential gravity is not appreciated. These data indicate that toad poisoning may be underestimated and that education on the seriousness of toad toxins could be a useful public health measure.

Lymphadenopathy is an early clinical sign in cutaneous leishmaniasis (CL), caused by Viannia parasites, and may help to understand the initial host response to these species of Leishmania. We report on characteristics of cells obtained from lymph nodes from cutaneous leishmaniasis patients with lymphadenopathy without ulceration (early phase, N = 21) or lymphadenopathy and ulceration (late phase, N = 29). Early-phase patients exhibited a higher proportion of neutrophils, eosinophils, and CD8+ T cells. Conversely, CD19+ B lymphocytes and plasma cells were more frequently observed in late-phase patients. The signal for IL-10 was significantly higher in late-phase patients; signals for IFN-γ or IL-4 were similar in both groups. These data reinforce observations of an initial mixed Th1–Th2 profile as well as the early role of the CD8 T cell in cutaneous leishmaniasis. Additionally, there is a chronologic relationship between ulcer development and B-cell increase. IL-10 also increases at a late stage and may be important in limiting tissue damage.

A popular hypothesis to explain parasite survival in the presence of a pronounced T helper 2 phenotype in helminth-parasitized populations has been FcϵRI blockade by parasite-induced polyclonal IgE. To begin to test the hypothesis that FcϵRI-bearing cells would be refractory to activation in parasitized populations, we investigated basophil function in 43 individuals from a hookworm endemic area. Study individuals had high levels of total IgE and eosinophilia and a mean hookworm burden of 2,257 epg. Basophils from all members of this parasitized population were shown to release histamine to a number of agonists, including anti IgE and a hookworm allergen, calreticulin. These data would indicate that FcϵRI blockade at the level of the basophil did not occur in this parasitized population despite the presence of possible immunologic blocking agents. This would suggest that this effector arm of the T helper 2 phenotype remains operative in infected populations.

We describe the design and report baseline results of a cluster-randomized intervention to determine the importance of bovines for Schistosoma japonicum transmission in southern China. The study involves four matched village pairs in Hunan and Jiangxi Provinces, with a village within each pair randomly selected as intervention (human and bovine praziquantel treatment) or control (human praziquantel treatment only). Total study population prevalences at baseline were 12.4% (n = 5,390) and 15.2% (n = 1,573) for humans and bovines, respectively; village prevalences were similar within pairs. Bovine contamination index calculations showed that bovines less than 24 months of age were responsible for 74% of daily bovine environmental contamination with S. japonicum eggs. The village characteristics and baseline results underpin a rigorous study, which has major implications for deployment of a transmission-blocking bovine vaccine against S. japonicum. The combination of such a vaccine with other control strategies could potentially eliminate S. japonicum from southern China.

We report a rare case of cardiac manifestation of cystic echinococcosis in a young Turkish patient. The patient had a history of cardiac surgery caused by a spontaneously ruptured cardiac mass that was intraoperatively diagnosed as a manifestation of cystic echinococcosis. Spread of the disease occurred in the lower mediastinum and pericardium. The patient was treated with antihelmintic medication in the postsurgical course. Follow-up was performed by cardiac magnetic resonance imaging (MRI) and dual-source cardiac–computed tomography (CT). We present the advantages and limitations of both imaging modalities in diagnosing cardiac manifestations of cystic echinococcosis and discuss their impact on therapy planning. We conclude that cardiac MRI and dual-source Cardio-CT contribute in a complimentary way to diagnosing and assessing cyst activity and extend of disease. Imaging plays a major role in the management of this disease because it can detect a response to antihelmintic medication or identify possible treatment options.

Endosymbionic Wolbachia bacteria inside adult Onchocerca volvulus worms (causing river blindness) are necessary for female worm fertility. We evaluated whether rifampin and/or azithromycin used in a five-day course could kill Wolbachia. In an open-label trial in Guatemala, 73 patients with 134 palpable onchocercal nodules were randomized into four treatment groups: rifampin, azithromycin, a combination of the two drugs, and controls (multivitamins). After five days of antibiotic treatment, all participants received a single dose of ivermectin on day 6. Nine months after treatment, the nodules were removed and the worms were examined. Skin snips to determine microfilariae were obtained at baseline and nine months. There were no significant differences between any of the treatment groups in the condition of the worms in the nodules, the presence of Wolbachia surface protein, or the number of microfilariae in skin. Short courses with these antibiotics will not clear Wolbachia from O. volvulus.