Research and Reports in Tropical Medicine最新文献

Onchocerciasis is a parasitic infection caused by the filarial nematode Onchocerca volvulus and transmitted through the bites of black flies of the genus Similium that breed in rivers and streams. The impact of mass treatment with ivermectin and supplemented by vector control in some countries has changed the global scene of onchocerciasis. There has been reported progress made in elimination of onchocerciasis in central and southern American countries and in some localities in Africa. The target for elimination in the Americas has been set at 2022 while for 12 countries in Africa this is expected in 2030. This review was conducted to examine the current status of onchocerciasis elimination at the global level and report on progress made. Literature searches were made through PubMed, articles in English or English abstracts, reports and any other relevant articles related to the subject. The global burden of onchocerciasis is progressively reducing and is no longer a public health problem in some regions. However, programs are challenged with a range of issues: cross-border transmission, diagnostic tools, Loa loa co-endemicity, limited workforce in entomology and maintaining enthusiasm among community drug distributors. More concerted effort using appropriate tools is required to overcome the challenges.

Schistosomiasis ranks second behind malaria in terms of overall morbidity and mortality. We evaluated the lethal effect of Punica granatum ellagitannins, extracted from the fruit rind, placenta and barks of the root and stem, on adult worms of Schistosoma mansoni (S. mansoni). All four ellagitannins were lethal to S. mansoni adult worms. However, while the rind ellagitannins were the most potent, placental ellagitannins were the least. Rind ellagitannins were capable of killing 40% of adult worms at a concentration of 25µg/mL after 5 days. The killing of 100% of the worms was achievable by rind ellagitannins at a concentration of 50µg/mL after 5 days. The LD_50S of the rind ellagitannins after 96h and 120h were 41.25 µg/mL and 28.73 respectively. Ellagitannins-treated worms suffered from erosions, wrinkles, swellings and losses, degenerations of the surface tubercles and tegument. In addition, ellagitannins induced deformation and degradation of oral and ventral suckers and degenerations in the muscles of worms. Ellagitannins also caused a separation of coupled worms and reduction of their motility. Data obtained suggest that ellagitannins of pomegranate could be considered as a cheap candidate for the treatment of schistosomiasis.

Background: Surveillance of the clinical morbidity of malaria remains key for disease monitoring for subsequent development of appropriate interventions. This case study presents the current status of malaria morbidities following a second round of mass distribution of long-lasting insecticidal nets (LLINs) on Ukerewe Island, northwestern Tanzania.

Methods: A retrospective review of health-facility registers to determine causes of inpatient morbidities for every admitted child aged <5 years was conducted to ascertain the contribution of malaria before and after distribution of LLINs. This review was conducted from August 2016 to July 2018 in three selected health facilities. To determine the trend of malaria admissions in the selected facilities, additional retrospective collection of all malaria and other causes of admission was conducted for both <5- and >5-year-old patients from July 2014 to June 2018. For comparison purposes, monthly admissions of malaria and other causes from all health facilities in the district were also collected. Moreover, an LLIN-coverage study was conducted among randomly selected households (n=684).

Results: Between August 2016 and July 2018, malaria was the leading cause of inpatient morbidity, accounting for 44.1% and 20.3% among patients <5 and >5 years old, respectively. Between October 2017 and January 2018, the mean number of admissions of patients aged <5 years increased 2.7-fold at one health center and 1.02-fold for all admissions in the district. Additionally, approximately half the households in the study area had poor of LLIN coverage 1 year after mass distribution.

Conclusion: This trend analysis of inpatient morbidities among children aged <5 years revealed an upsurge in malaria admissions in some health facilities in the district, despite LLIN intervention. This suggests the occurrence of an unnoticed outbreak of malaria admissions in all health facilities.

Purpose: CD4+ T-lymphocytopenia is a risk for tuberculosis (TB) infection, reactivation and severe disease. We sought to determine the prevalence and predictors of CD4 T-lymphocytopenia among HIV-negative patients with bacteriologically confirmed TB in Uganda.

Patients and methods: Eligible participants were adult HIV-negative patients with bacteriologically confirmed TB at the National TB Treatment Centre in Uganda. CD4+ and CD8+ T-lymphocyte counts were determined by flow cytometry. We defined CD4+ T-lymphocytopenia as a CD4+ T-lymphocyte count of <418 cells/mm³ as per the population estimate for Ugandans. We performed logistic regression analysis to determine predictors of CD4+ T-lymphocytopenia.

Results: We enrolled 216 participants whose mean age (standard deviation (±SD)) was 32.5 (±12.1) years, of whom 146 (67.6%) were males. The prevalence of CD4+ T-lymphocytopenia was 25% (54/216) (95% confidence interval (CI): 19.6-31.2%). Patients with anaemia (adjusted odds ratio (aOR): 3.83, 95% CI: 1.59-9.23, p = 0.003), weight loss (aOR: 3.61, 95% CI: 1.07-12.23, p = 0.039) and a low CD8+ T-cell count (aOR: 6.10, 95% CI: 2.68-13.89, p < 0.001) were more likely to have CD4+ T-lymphocytopenia while those with monocytosis (aOR: 0.35, 95% CI: 0.14-0.89, p = 0.028) were less likely to have CD4+ T-lymphocytopenia.

Conclusion: There was a high prevalence of CD4+ T-lymphocytopenia among HIV-negative TB patients. Patients with weight loss, anaemia and a low CD8+ count were more likely to have CD4+ T-lymphocytopenia while those with monocytosis were less likely to have CD4+ lymphocytopenia. The findings suggest that CD4+ lymphocytopenia is indicative of severe disease and globally impaired cell-mediated immune responses against TB.

Background: Malaria is increasingly characterized by appreciable fine-scale variability in ecology and topography, and it is likely that we are missing some salient foci with unprecedented malaria transmission intensity in different parts of Tanzania. Therefore, efforts aimed at identifying area-specific malaria situation and intervening are needed to preserve the realized health gains and achieve elimination. Mkuyuni and Kiroka, adjacent wards within Morogoro Rural District, are purported to form one of such foci.

Patients and methods: A retrospective study was conducted to determine six-year (2014-2019) malaria prevalence rates based on outpatients and laboratory registers obtained from two health facilities, one per ward, carrying out diagnosis of malaria either through microscopy or malaria rapid diagnostic test (mRDT). These data were checked for completeness before carrying out statistical analysis.

Results: Overall, 35,386 (46.19%) out of 76,604 patients were positive for malaria. The average proportion of malaria cases was significantly higher in Mkuyuni (51.23%; n=19,438) than Kiroka (41.21%; n = 15,938) (P <0.001). Females were more affected than males (P <0.001);, and irrespective of the sex, most malaria cases were recorded in children <5 years of age (P <0.001) except at Mkuyuni. Malaria was recorded virtually all year round; however, the highest proportion of cases was recorded in April and July (P <0.001).

Conclusion: This study revealed high malaria endemicity in Mkuyuni and Kiroka, with prevalence rate as high as 60.98%, which is far higher than the overall national average prevalence of 9%. More studies are needed in these and other putatively high endemic foci in Tanzania in order to inform the future course of action in disease surveillance and control.

Purpose: To assess basic coagulation profiles and platelet count among Schistosoma mansoni-infected and non-infected adults.

Patients and methods: A comparative cross-sectional study was conducted from February to April 2019 at Sanja Primary Hospital, northwest Ethiopia. A total of 200 adults (100 cases and 100 controls) were enrolled using convenient sampling technique. Both wet mount and Kato-Katz techniques were performed using a stool sample. The venous blood sample was collected to perform platelet count, basic coagulation and serological tests. The data were coded and entered into EpiData Manager (v4.4.2.1) and analyzed using SPSS version 20. Nonparametric tests were used during data analysis. P-value less than 0.05 was considered as statistically significant.

Results: Prothrombin time (PT), activated partial thromboplastin time (APTT) and international normalization ratio (INR) were significantly higher while the platelet count was significantly lower in S. mansoni-infected than healthy adults (P <0.001). There were statistically significant differences in the median [IQR] value of PT, APTT, INR and platelet count between light, moderate and heavy infected groups (P <0.05). Infection intensity had a positive correlation with basic coagulation profiles and a negative correlation with platelet count (P <0.05) of S. mansoni-infected adults.

Conclusion: The prevalence of coagulation abnormality was higher in S. mansoni-infected adults than healthy controls. Coagulation test and platelet count should be used to monitor and manage schistosomiasis-related complications.

Background: Fruits and vegetables, which are consumed raw, act as potential sources for the spread of various parasitic diseases. The rate of contamination and species of contaminant parasites varies based on climatic, ecological, and human factors. Therefore, local data about the contamination status and predisposing factors augments efforts for successful control of parasitic diseases.

Methods: A cross-sectional study was conducted on fruits and vegetables collected from local markets of Bahir Dar city from February to May 2019. A total of 384 samples were purchased from three randomly selected markets. Data on sociodemographic characteristics of vendors and factors associated with contamination of fruits and vegetables were collected using a structured questionnaire. About 200 g of fruit and vegetable samples were processed for parasites using direct wet mount and modified Zeihl-Neelson staining techniques following standard protocols. All data were analyzed using SPSS version 23.

Results: Among a total of 384 fruit and vegetable samples purchased from 112 vendors, 150 (39.1%) were contaminated with at least one species of parasite. Lettuce (56.4%) and mango (16.7%) were the most and the least commonly contaminated items respectively. Larva of Strongyloides species (13.5%) was the most frequently detected parasite followed by cysts of Entamoeba histolytica/E. dispar (12.8%). Contamination was more common in vegetables than fruits (AOR=2.968, p<0.001). Fruits and vegetables purchased from vendors with untrimmed fingernails (AOR=1.966, p=0.006), directly delivered from farmers (AOR=1.883, p=0.040), displayed in bucket with water (AOR=2.676, p=0.017) and those displayed without washing (AOR=5.511, p<0.001) were significantly associated with parasitic contamination.

Conclusion: The level of parasitic contamination of fruits and vegetables in Bahir Dar city is of public health importance. Hence, the public health sector should create public awareness in order to reduce parasitic transmission via fruits and vegetables.

Background: Tuberculosis (TB) remains a foremost global public health threat. Active TB control needs geographically accessible health facilities that have quality diagnostics, equipment, supplies, medicines, and staff.

Objective: This study aimed at assessing the geographic distribution, physical accessibility, readiness and barriers of health facilities for TB services in East Gojjam zone, Ethiopia.

Methods: A convergent parallel design was applied using health facility and geographic data. Data on facility attributes, service availability and readiness were collected by inteviewing TB officers, laboratory heads and onsite facility visits. Coordinates of health facilities and kebele centroids were collected by GPS. We used ArcGIS 10.6 to measure Euclidean distance from each kebele centroids to the nearest health facility. Descriptive statistics were computed by using SPSS version 25. Barriers to TB service readiness were explored by in-depth interviews. NVivo12 was used to thematically analyze the qualitative data.

Results: The overall TB health service coverage (THSC) was 23% (ranging: 10-85%). The mean distance from the nearest health facility was 8km (ranging: 0.5-16km). About 132 (32%) kebeles had poor geographic accessibility to TB services (over 10km distance from the nearest health facility) and had poor facility readiness. Although 114 (95%) health facilities offered at least one TB service, 44 (38.6%) of them had no sputum smear microscopy. The overall TB readiness index was 63.5%: first-line anti-TB drugs (97%), diagnostics (63%), trained staffs, diagnostic and treatment guidelines (53%) and laboratory supplies (41%). Lack of health workers (laboratory personnel), inadequate budget, poor management practice and TB program support, inadequate TB commodity suppliers, and less accessible geographic locations of health facilities were identified as barriers to TB service readiness distribution.

Conclusion: Considerable proportion of the population in the study area  have poor access to quality TB diagnostic services due to low THSC and poor facility readiness. Barriers to TB service availability and readiness were health system related. Regular refresher training of health workers on TB, creating mechanisms to attract laboratory personnel to work in the study area and scaling up of sputum smear microscopy services, establishing an efficient mechanism for procurement, distribution, utilization and reporting of TB commodity supplies, and good management practices are crucial to enhance TB service readiness in the study zone.