485 research outputs found
Smear positive pulmonary tuberculosis among HIV patients receiving Highly Active Antiretroviral Therapy in Dar es Salaam, Tanzania
No full textGlobally, tuberculosis-HIV co-infections are on the increase. In 2007,
15% (1.37 million) of the tuberculosis cases were HIV-positive
tuberculosis (TB). This cross-sectional study was conducted in February
2009 to assess the effect of the level of CD4 lymphocyte counts on the
development of smear positive pulmonary TB (PTB) among HIV patients
before and after initiation of highly active antiretroviral therapy
(HAART). A total of 155 HIV patients who were on HAART programme were
enrolled and out of these 42 (27.1%) were smear positive PTB. Of the 42
PTB patients, 38 (90.5%) were also infected with HIV and were already
at initiation of HAART. There was no association between the
development of smear positive PTB and socio-demographic characteristics
among HIV patients before and after HAART initiation (P>0.05). A
larger proportion of HIV+PTB patients diagnosed before and after HAART
initiation was found with CD4 lymphocyte count <200cells/µl.
However, the difference was not statistically significant (P=0.092).
Among HIV patients who were diagnosed to be smear positive PTB after
HAART initiation, their CD4 lymphocyte counts at time of TB diagnosis
was lower than their CD4 lymphocyte counts at time of HAART initiation.
The four patients diagnosed with PTB after HAART initiation had mean
CD4 lymphocyte counts at HAART initiation not statistically different
from that at TB diagnosis (t=0.715, P=0.526).The median time period
within which the diagnosis of smear positive PTB was made after HAART
initiation was 22 weeksand the mean time was 66.75 weeks. These
findings provide evidence that development of smear positive PTB after
HAART initiation may occur at any level of CD4 lymphocyte count
(P<0.05). This study was limited by the relatively small sample
size, we therefore recommend more studies involving a larger sample
size in order to estimate more accurately the effect of both level of
CD4 lymphocyte count and HAART on the development of smear positive PTB
among HIV patients on treatment
Biochemical basis of permethrin resistance in Anopheles arabiensis from Lower Moshi, north-eastern Tanzania.
No full textBACKGROUND: Development of resistance to different classes of insecticides is a potential threat to malaria control. With the increasing coverage of long-lasting insecticide-treated nets in Tanzania, the continued monitoring of resistance in vector populations is crucial. It may facilitate the development of novel strategies to prevent or minimize the spread of resistance. In this study, metabolic-based mechanisms conferring permethrin (pyrethroid) resistance were investigated in Anopheles arabiensis of Lower Moshi, Kilimanjaro region of north-eastern Tanzania. METHODS: WHO susceptibility test kits were used to detect resistance to permethrin in An. arabiensis. The levels and mechanisms of permethrin resistance were determined using CDC bottle bioassays and microplate (biochemical) assays. In bottle bioassays, piperonyl butoxide (PBO) and s,s,s-tributyl phosphorotrithioate (DEF) were used as synergists to inhibit mixed function oxidases and non-specific esterases respectively. Biochemical assays were carried out in individual mosquitoes to detect any increase in the activity of enzymes typically involved in insecticide metabolism (mixed function oxidases, alpha- and beta-esterases). RESULTS: Anopheles arabiensis from the study area was found to be partially resistant to permethrin, giving only 87% mortality in WHO test kits. Resistance ratios at KT50 and KT95 were 4.0 and 4.3 respectively. The permethrin resistance was partially synergized by DEF and by PBO when these were mixed with permethrin in bottle bioassays and was fully synergized when DEF and PBO were used together. The levels of oxidase and beta-esterase activity were significantly higher in An. arabiensis from Lower Moshi than in the laboratory susceptible strain. There was no difference in alpha-esterase activity between the two strains. CONCLUSION: Elevated levels of mixed function oxidases and beta-esterases play a role in detoxification of permethrin in the resistant An. arabiensis population of Lower Moshi
Smear positive pulmonary tuberculosis among HIV patients receiving Highly Active Antiretroviral Therapy in Dar es Salaam, Tanzania
No full textGlobally, tuberculosis-HIV co-infections are on the increase. In 2007,
15% (1.37 million) of the tuberculosis cases were HIV-positive
tuberculosis (TB). This cross-sectional study was conducted in February
2009 to assess the effect of the level of CD4 lymphocyte counts on the
development of smear positive pulmonary TB (PTB) among HIV patients
before and after initiation of highly active antiretroviral therapy
(HAART). A total of 155 HIV patients who were on HAART programme were
enrolled and out of these 42 (27.1%) were smear positive PTB. Of the 42
PTB patients, 38 (90.5%) were also infected with HIV and were already
at initiation of HAART. There was no association between the
development of smear positive PTB and socio-demographic characteristics
among HIV patients before and after HAART initiation (P>0.05). A
larger proportion of HIV+PTB patients diagnosed before and after HAART
initiation was found with CD4 lymphocyte count <200cells/µl.
However, the difference was not statistically significant (P=0.092).
Among HIV patients who were diagnosed to be smear positive PTB after
HAART initiation, their CD4 lymphocyte counts at time of TB diagnosis
was lower than their CD4 lymphocyte counts at time of HAART initiation.
The four patients diagnosed with PTB after HAART initiation had mean
CD4 lymphocyte counts at HAART initiation not statistically different
from that at TB diagnosis (t=0.715, P=0.526).The median time period
within which the diagnosis of smear positive PTB was made after HAART
initiation was 22 weeksand the mean time was 66.75 weeks. These
findings provide evidence that development of smear positive PTB after
HAART initiation may occur at any level of CD4 lymphocyte count
(P<0.05). This study was limited by the relatively small sample
size, we therefore recommend more studies involving a larger sample
size in order to estimate more accurately the effect of both level of
CD4 lymphocyte count and HAART on the development of smear positive PTB
among HIV patients on treatment
Effect of different hosts on feeding patterns and mortality of mosquitoes (Diptera: Culicidae) and their implications on parasite transmission
No full textAim: The host-response to hematophagus insects is still an important parameter in understanding disease transmission patterns. We investigated the feeding and mortality rates of three mosquito species, namely Culex quinquefasciatus, Aedes aegypti and Anopheles arabiensis against three different hosts. Materials and Methods: Unfed three to five-day-old female mosquitoes were released in a tunnel box that had a rabbit or guinea pig or mice as a host. The feeding succession patterns of mosquitoes in different hosts were An. arabiensis, Cx. quinquefasciatus and A. aegypti. Results: Mosquito mortality rate was 54.9% for mosquitoes introduced in mice as a host, 34.3% in the Guinea pig and 10.8% for those that introduced in the rabbit. Conclusion: The presence of defensive and tolerable hosts in environment emphasizes the relevance of studying epidemiological impact of these behaviors in relation to diseases transmission
Insecticide use pattern and phenotypic susceptibility of Anopheles gambiae sensu lato to commonly used insecticides in Lower Moshi, northern Tanzania
No full textAbstract Background Evidence of insecticide resistance has been documented in different malaria endemic areas. Surveillance studies to allow prompt investigation of associated factors to enable effective insecticide resistance management are needed. The objective of this study was to assess insecticide use pattern and phenotypic susceptibility level of Anopheles gambiae sensu lato to insecticides commonly used in malaria control in Moshi, northern Tanzania. Methods A cross-sectional survey was conducted to assess insecticide usage pattern. Data was collected was through closed and open ended questionnaires The WHO diagnostic standard kit with doses of 0.1% bendiocarb, 0.05% deltamethrin, 0.75% permethrin and 4% DDT were used to detect knockdown time, mortality and resistance ratio of wild A. gambiae sensu lato. The questionnaire survey data was analyzed using descriptive statistics and one-way analysis of variance while susceptibility data was analysed by logistic regression with probit analysis using SPSS program. The WHO criteria was used to evaluate the resistance status of the tested mosquito populations. Results A large proportion of respondents (80.8%) reported to have used insecticide mainly for farming purposes (77.3%). Moreover, 93.3% of household reported usage of long lasting insecticidal nets. The frequently used class of insecticide was organophosphate with chloropyrifos as the main active ingredients and dursban was the brand constantly reported. Very few respondents (24.1%) applied integrated vector control approaches of and this significantly associated with level of knowledge of insecticide use (P < 0.001). Overall knockdown time for A. gambiae s.l was highest in DDT, followed by Pyrethroids (Permethrin and deltamethrin) and lowest in bendiocarb. Anopheles gambiae s.l showed susceptibility to bendiocarb, increased tolerance to permethrin and resistant to deltamethrin. The most effective insecticide against the population from tested was bendiocarb, with a resistance ratio ranging between 0.93–2.81. Conclusion Education on integrated vector management should be instituted and a policy change on insecticide of choice for malaria vector control from pyrethroids to carbamates (bendiocarb) is recommended. Furthermore, studies to detect cross resistance between pyrethroids and organophosphates should be carried out
Insecticide use pattern and phenotypic susceptibility of Anopheles gambiae sensu lato to commonly used insecticides in Lower Moshi, northern Tanzania
No full textColonization and Authentication of the Pyrethroid-Resistant Anopheles gambiae s.s. Muleba-Kis Strain; an Important Test System for Laboratory Screening of New Insecticides.
No full textBACKGROUND: The emergence and spread of insecticide resistance in malaria vectors to major classes of insecticides call for urgent innovation and application of insecticides with novel modes of action. When evaluating new insecticides for public health, potential candidates need to be screened against both susceptible and resistant mosquitoes to determine efficacy and to identify potential cross-resistance to insecticides currently used for mosquito control. The challenges and lessons learned from establishing, maintaining, and authenticating the pyrethroid-resistant An. gambiae s.s. Muleba-Kis strain at the KCMUCo-PAMVERC Test Facility are described in this paper. METHODS: Male mosquitoes from the F1 generation of wild-pyrethroid resistant mosquitoes were cross-bred with susceptible female An. gambiae s.s. Kisumu laboratory strain followed by larval selection using a pyrethroid insecticide solution. Periodic screening for phenotypic and genotypic resistance was done. WHO susceptibility tests and bottle bioassays were used to assess the phenotypic resistance, while Taqman™ assays were used to screen for known target-site resistance alleles (kdr and ace-1). Additionally, the strains were periodically assessed for quality control by monitoring adult weight and wing length. RESULTS: By out-crossing the wild mosquitoes with an established lab strain, a successful resistant insectary colony was established. Intermittent selection pressure using alphacypermethrin has maintained high kdr mutation (leucine-serine) frequencies in the selected colony. There was consistency in the wing length and weight measurements from the year 2016 to 2020, with the exception that one out of four years was significantly different. Mean annual wing length varied between 0.0142-0.0028 mm compared to values obtained in 2016, except in 2019 where it varied by 0.0901 mm. Weight only varied by approximately 0.001 g across four years, except in 2017 where it differed by 0.005 g. Routine phenotypic characterization on Muleba-Kis against pyrethroids using the WHO susceptibility test indicated high susceptibility when type I pyrethroids were used compared to type II pyrethroids. Dynamics on susceptibility status also depended on the lapse time when the selection was last done. CONCLUSIONS: This study described the procedure for introducing, colonizing, and maintaining a resistant An. gambiae s.s. strain in the laboratory with leucine to serine substitution kdr allele which reflects the features of the wild-resistant population in East Africa. Challenges in colonizing a wild-resistant mosquito strain were overcome by out-crossing between mosquito strains of desired traits followed by intermittent insecticide selection at the larval stage to select for the resistant phenotype
Water, sanitation and hygiene (WASH) in schools: results from a process evaluation of the National Sanitation Campaign in Tanzania
No full textThis study assesses the intermediate outcomes of the Tanzania National Sanitation Campaign (NSC) for schools. A cross-sectional study was designed as part of a process evaluation of the NSC in Tanzania on 70 primary schools and 54 regional and district education officers. Data was collected between August and December 2014 using questionaires, key informant interviews, and desk studies. The results showed that only 50% of schools met the Tanzania guideline of 50 boys per drop hole, while 43% met the guideline of 40 girls per drop hole. In addition, 53% of schools had a reliable water supply, 43% had some functional handwashing stations, but only 29% and 19% had water and soap available at the stations, respectively. Overall, the implementation of the NSC in schools was found to be effective, though poor planning and coordination, inadequate funding, and low technical capacity were identified as barriers to achieve the intended objectives. The study recommends stronger and coordinated stakeholder partnerships with clearly defined roles including cost sharing. Government and other stakeholders should also consider the impact of increasing funding for both software and hardware components to improve the enabling environment, and to develop a standardised monitoring mechanism for sustainable school water, sanitation and hygiene
Users' and health service providers' perception on quality of laboratory malaria diagnosis in Tanzania
No full textAbstract Background Correct diagnosis of malaria is crucial for proper treatment of patients and surveillance of the disease. However, laboratory diagnosis of malaria in Tanzania is constrained by inadequate infrastructure, consumables and insufficient skilled personnel. Furthermore, the perceptions and attitude of health service providers (laboratory personnel and clinicians) and users (patients/care-takers) on the quality of laboratory services also present a significant challenge in the utilization of the available services. This study was conducted to assess perceptions of users and health-care providers on the quality and utilization of laboratory malaria diagnostic services in six districts from three regions in Tanzania. Methods Questionnaires were used to collect information from laboratory personnel, clinicians and patients or care-takers. Results A total of 63 laboratory personnel, 61 clinicians and 753 patients/care-takers were interviewed. Forty-six (73%) laboratory personnel claimed to be overworked, poorly motivated and that their laboratories were under-equipped. About 19% (N = 12) of the laboratory personnel were lacking professional qualification. Thirty-seven clinicians (60.7%) always requested for blood smear examination to confirm malaria. Only twenty five (41.0%) clinicians considered malaria microscopy results from their respective laboratories to be reliable. Forty-five (73.8%) clinicians reported to have been satisfied with malaria diagnostic services provided by their respective laboratories. Majority (90.2%, N = 679) of the patients or care-takers were satisfied with the laboratory services. Conclusion The findings show that laboratory personnel were not satisfied with the prevailing working conditions, which were reported to undermine laboratory performance. It was evident that there was no standard criteria for ordering malaria laboratory tests and test results were under-utilized. Majority of the clinicians and patients or care-takers were comfortable with the overall performance of laboratories, but laboratory results were having less impact on patient management.</p
The Impact of Submicroscopic Parasitemia on Malaria Rapid Diagnosis in Northeastern Tanzania, an Area with Diverse Transmission Patterns
No full textGlobal malaria epidemiology has changed in the last decade with a substantial increase in cases and deaths being recorded. Tanzania accounts for about 4% of all cases and deaths reported in recent years. Several factors contribute to the resurgence of malaria, parasite resistance to antimalarials and mosquito resistance to insecticides being at the top of the list. The presence of sub-microscopic infections poses a significant challenge to malaria rapid diagnostic tests (mRDT). Our cross-sectional surveys in Handeni and Moshi, Tanzania assessed the effect of low parasite density on mRDT. Handeni had higher malaria prevalence by mRDT (39.6%), light microscopy (LM) (16.9%) and polymerase chain reaction (PCR) (18.5%), compared to Moshi with prevalence of 0.2%, 1.3% and 2.3%, respectively. A significant difference (p ˂ 0.001) in malaria prevalence by mRDT, LM and nested PCR was found among age groups. In comparison to all other groups, school-age children (5–15 years) had the highest prevalence of malaria. Our results show that mRDT may miss up to 6% of cases of malaria mainly due to low-density parasitemia when compared to LM and PCR. Routinely used mRDT will likely miss the sub-microscopic parasitemia which will ultimately contribute to the spread of malaria and hinder efforts of elimination
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