Prevalence of dengue and chikungunya virus infections in north-eastern Tanzania:a cross sectional study among participants presenting with malaria-like symptoms

BACKGROUND: In spite of increasing reports of dengue and chikungunya activity in Tanzania, limited research has been done to document the general epidemiology of dengue and chikungunya in the country. This study aimed at determining the sero-prevalence and prevalence of acute infections of dengue and chikungunya virus among participants presenting with malaria-like symptoms (fever, headache, rash, vomit, and joint pain) in three communities with distinct ecologies of north-eastern Tanzania. METHODS: Cross sectional studies were conducted among 1100 participants (aged 2–70 years) presenting with malaria-like symptoms at health facilities at Bondo dispensary (Bondo, Tanga), Hai hospital (Hai, Kilimanjaro) and TPC hospital (Lower Moshi). Participants who were malaria negative using rapid diagnostic tests (mRDT) were screened for sero-positivity towards dengue and chikungunya Immunoglobulin G and M (IgG and IgM) using ELISA-based kits. Participants with specific symptoms defined as probable dengue and/or chikungunya by WHO (fever and various combinations of symptoms such as headache, rash, nausea/vomit, and joint pain) were further screened for acute dengue and chikungunya infections by PCR. RESULTS: Out of a total of 1100 participants recruited, 91.2 % (n = 1003) were malaria negative by mRDT. Out of these, few of the participants (<5 %) were dengue IgM or IgG positive. A total of 381 participants had fever out of which 8.7 % (33/381) met the defined criteria for probable dengue, though none (0 %) was confirmed to be acute cases. Chikungunya IgM positives among febrile participants were 12.9 % (49/381) while IgG positives were at 3.7 % (14/381). A total of 74.2 % (283/381) participants met the defined criteria for probable chikungunya and 4.2 % (11/263) were confirmed by PCR to be acute chikungunya cases. Further analyses revealed that headache and joint pain were significantly associated with chikungunya IgM seropositivity. CONCLUSION: In north-eastern Tanzania, mainly chikungunya virus appears to be actively circulating in the population. Continuous surveillance is needed to determine the contribution of viral infections of fever cases. A possible establishment of arboviral vector preventive control measures and better diagnosis of pathogens to avoid over-treatment of other diseases should be considered. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12879-016-1511-5) contains supplementary material, which is available to authorized users

Mapping clusters of chikungunya and dengue transmission in northern Tanzania using disease exposure and vector data

Background: Dengue and chikungunya are mosquito-borne viral diseases that are of public health importance throughout the tropical and subtropical regions of the world. Seasonal variations in transmission of these viruses have been suggested owing to the ecology of their mosquito vectors. However, little is known about the epidemiology of the diseases Tanzania. To address this gap, seasonal community-based cross-sectional surveys were undertaken to identify potential clusters of transmission in Hai district in northern Tanzania.Methods: Epidemiological and entomological data from two cross-sectional surveys were used to examine the spatial pattern of dengue and chikungunya transmission. Six villages namely, Boma Ng’ombe, Magadini, Rundugai, Nshara and Kware were involved in the study. Serological measures of dengue and chikungunya virus infections were derived using enzyme-linked immunosorbent assays, and all participants were geo-referenced to the household level using a global positioning system. Potential clusters of individual exposed to dengue and chikungunya virus , as well as clusters of Aedes mosquitoes in the wet and dry seasons were detected using SaTScan. All significant clusters (with p≤0.05) were mapped using ArcGIS.Results: A large, widely dispersed cluster of chikungunya exposed individuals was detected spanning Rundugai and parts of Magadini villages (RR = 2.58,  p= 0.01), while no significant clustering was observed in the dry season. Spatial clusters of Aedes aegypti were detected in Rundugai in both the wet and dry seasons (RR = 2.56, p&lt; 0.001 and RR = 2.24, p=0.05, respectively). In the dry season a small cluster was also detected in Kware (RR = 2.25, p=0.05). No significant clusters of dengue were detected in both seasons.Conclusion: Clusters of chikungunya-exposed individuals and Aedes mosquitoes indicate on-going transmission of chikungunya virus in Hai district of northern Tanzania

The evolution of haematological and biochemical indices in HIV patients during a six-month treatment period

Objective: To assess haematological and biochemical parameters in Human Immunodeficiency Virus (HIV) patients under going antiretroviral therapy. Methods: We enrolled HIV patients from, 18-65 years, who were under first line antiretroviral therapy and followed them for six months from February 2010 for changes in haematological and biochemical parameters. Profiles for ALAT, creatinine, amylase, cholesterol, CD4+ and total lymphocytes, haemoglobin, and monocytes were studied every three months. Results: There was an increase of both, CD4+ lymphocyte counts from 233.57 cells/mm3 to 336.45 cells/mm3 and total lymphocytes from 45 to 46.6 103 cells /μl, after six months. The haemoglobin level dropped from 8.8 g/L to 7.52 g/L. We observed an increase in ALAT from 40.27 to 47.42 U/L, amylase from 178.9 to 193.97 U/L, and cholesterol from 5.88 to 8.40 mmol/L. Creatinine levels decreased from 117.4 to 115.0 μmol/L. Conclusion: The use of ARVs boosts CD4+ and total lymphocyte counts. Prolonged use of antiretroviral drugs (ARVs) is associated with variable degrees of liver and pancreatic damage, hypercholesteremia, and anaemia in some patients. Since many of these side effects are multi-factorial, management of HIV patients should take into consideration such side effects in making treatment decisions based on periodic evaluation of these parameter

The evolution of haematological and biochemical indices in HIV patients during a six-month treatment period

Objective: To assess haematological and biochemical parameters in Human Immunodeficiency Virus (HIV) patients under going antiretroviral therapy. Methods: We enrolled HIV patients from, 18-65 years, who were under first line antiretroviral therapy and followed them for six months from February 2010 for changes in haematological and biochemical parameters. Profiles for ALAT, creatinine, amylase, cholesterol, CD4+ and total lymphocytes, haemoglobin, and monocytes were studied every three months. Results: There was an increase of both, CD4+ lymphocyte counts from 233.57 cells/mm3 to 336.45 cells/mm3 and total lymphocytes from 45 to 46.6 103 cells /μl, after six months. The haemoglobin level dropped from 8.8 g/L to 7.52 g/L. We observed an increase in ALAT from 40.27 to 47.42 U/L, amylase from 178.9 to 193.97 U/L, and cholesterol from 5.88 to 8.40 mmol/L. Creatinine levels decreased from 117.4 to 115.0 μmol/L. Conclusion: The use of ARVs boosts CD4+ and total lymphocyte counts. Prolonged use of antiretroviral drugs (ARVs) is associated with variable degrees of liver and pancreatic damage, hypercholesteremia, and anaemia in some patients. Since many of these side effects are multi-factorial, management of HIV patients should take into consideration such side effects in making treatment decisions based on periodic evaluation of these parameter

Healthcare workers knowledge and diagnostic practices: a need for dengue and chikungunya training in Moshi Municipality, Kilimanjaro Tanzania

Abstract Objective Dengue and chikungunya virus diseases are becoming an increasingly important global health threats and are continuously expanding their geographical range. The study aims to investigate knowledge and diagnostic practice of dengue and chikungunya fever among healthcare workers in Moshi Municipality. Results Most of healthcare workers heard of chikungunya and dengue 146 (71.2%) and 203 (99%) respectively. Ninety-five (46.3%) and 152 (74.1%) had good knowledge regard chikungunya and dengue respectively. One hundred and twenty-two of HCWs 122 (59.5%) reported that there is no vaccination for dengue virus. Most HCWs 199 (97.0%) reported that the absence of diagnostic tool for dengue virus lead to difficult in managing the infection. The finding of this study showed that there is insufficient knowledge regarding chikungunya while knowledge regarding dengue is relatively fair. This calls for training regarding these infections

Predictive markers of transmission in areas with different malaria endemicity in north-eastern Tanzania based on seroprevalence of antibodies against Plasmodium falciparum

Abstract Objective A community-based cross-sectional study was done to assess Plasmodium falciparum exposure in areas with different malaria endemicity in north-eastern Tanzania using serological markers; PfAMA-1 and PfMSP-119. Results Bondo had a higher seroprevalence 36.6% (188) for PfAMA-1 as compared to Hai 13.8% (33), χ2 = 34.66, p &lt; 0.01. Likewise, Bondo had a higher seroprevalence 201(36.6%) for PfMSP-1 as compared to Hai 41 (17.2%), χ2 = 29.62, p &lt; 0.01. Anti-PfAMA-1 titters were higher in malaria positive individuals (n = 47) than in malaria negative individuals (n = 741) (p = 0.07). Anti-PfMSP-1 antibody concentrations were significantly higher in malaria-positive individuals (n = 47) than in malaria-negative individuals (n = 741) (p = 0.003). Antibody response against PfAMA-1 was significantly different between the three age groups; &lt; 5 years, 5 to 15 years and &gt; 15 years in both sites of Bondo and Hai. Likewise, antibody response against PfMSP-119 was significantly different between the three age groups in the two sites (p &lt; 0.001). We also found significant differences in the anti-PfAMA-1and anti-PfMSP-119 antibody concentrations among the three age groups in the two sites (p = 0.004 and 0.005) respectively. Immunological indicators of P. falciparum exposure have proven to be useful in explaining long-term changes in the transmission dynamics, especially in low transmission settings. </jats:sec

Human IgG responses to <i>Aedes</i> mosquito salivary peptide Nterm-34kDa and its comparison to <i>Anopheles </i>salivary antigen (gSG6-P1) IgG responses measured among individuals living in Lower Moshi, Tanzania

BACKGROUND: The level of human exposure to arbovirus vectors, the Aedes mosquitoes, is mainly assessed by entomological methods which are labour intensive, difficult to sustain at a large scale and are affected if transmission and exposure levels are low. Alternatively, serological biomarkers which detect levels of human exposure to mosquito bites may complement the existing epidemiologic tools as they seem cost-effective, simple, rapid, and sensitive. This study explored human IgG responses to an Aedes mosquito salivary gland peptide Nterm-34kDa in Lower Moshi, a highland area with evidence of circulating arboviruses and compared the Aedes IgG responses to Anopheles mosquitoes' salivary antigen (GSG6-P1) IgG responses.METHODS: Three cross-sectional surveys were conducted in 2019: during the first dry season in March, at the end of the rainy season in June and during the second dry season in September in five villages located in Lower Moshi. Blood samples were collected from enrolled participants above six months of age (age span: 7 months to 94 years) and analysed for the presence of anti-Nterm-34kDa IgG antibodies. Possible associations between Nterm-34kDa seroprevalence and participants' characteristics were determined. Levels of IgG responses and seroprevalence were correlated and compared to the already measured IgG responses and seroprevalence of Anopheles mosquitoes' salivary antigen, GSG6-P1.RESULTS: During the first dry season, Nterm-34kDa seroprevalence was 34.1% and significantly increased at the end of the rainy season to 45.3% (Chi square (χ2) = 6.42 p = 0.011). During the second dry season, the seroprevalence significantly declined to 26.5% (χ2 = 15.12 p&lt;0.001). During the rainy season, seroprevalence was significantly higher among residents of Oria village (adjusted odds ratio (AOR) = 2.86; 95% CI = 1.0-7.8; p = 0.041) compared to Newland. Moreover, during the rainy season, the risk of exposure was significantly lower among individuals aged between 16 and 30 years (AOR = 0.25; 95% CI = 0.1 = 0.9; p = 0.036) compared to individuals aged between 0 and 5 years. There was weak to moderate negative correlation between N-term 34kDa IgG and gSG6-P1 antigens. N-term 34kDa seroprevalence were higher compared to gSG6-P1 seroprevalence.CONCLUSION: The findings of this study support that IgG antibody responses towards the Aedes mosquito salivary peptide Nterm-34kDa are detectable among individuals living in lower Moshi and vary with season and geographical area. More individuals are exposed to Aedes mosquito bites than Anopheles mosquito and those exposed to Aedes bites are not necessarily exposed to Anopheles mosquitoes.</p

Additional file 3 of Predictive markers of transmission in areas with different malaria endemicity in north-eastern Tanzania based on seroprevalence of antibodies against Plasmodium falciparum

Additional file 3: Figure S2. A graph showing mean OD values for PfAMA-1 (A) and PfMSP-119 (B) among malaria positive and negative individuals. Presented in the Y-axis is the Log10 transformed OD values among malaria positives and negatives (X-axis)

Prevalence and Associated Factors of Dengue Virus Circulation in the Rural Community, Handeni District in Tanga, Tanzania

Dengue virus is among the most important re-emerging arbovirus that causes global public health attention. Dengue has historically been thought of as an urban disease that frequently occurs in rapidly urbanized settings. However, dengue has become more widespread in rural regions in recent years. Understanding the changing dengue epidemiology in different geographical settings is important for targeted intervention. In Tanzania, dengue fever is not frequently reported because of the poor surveillance infrastructure, underestimation, and a lack of consideration of dengue as a priority. Therefore, the true burden as well as the risk factors for increased transmission has not been fully ascertained, particularly in rural areas. A cross-sectional community-based study was conducted in June 2021, involving a total of 362 participants of all age groups. We investigated the prevalence of acute dengue infection, seroprevalence, and associated factors among the community in three villages of the rural Handeni district. The prevalence of acute dengue infection (based on PCR) was 2.2% (8/362). Dengue-specific IgM and IgG antibodies were detected in 3.3% (12/362) and 5.2% (19/362) of the participants, respectively. Adult participants who were having vegetation around their houses were more likely to be DENV seropositive (AOR = 2.4, CI = 1.88–4.18, p value = 0.05). Children living in houses with garbage pit around their households were less likely to be DENV seropositive (AOR = 0.13, CI = 0.03–0.56, p value <0.01). DENV continues to circulate in rural Tanzania, causes an alarming situation, and necessitates prompt public health action to enhance vector surveillance and control in rural communities