ABSTRACT
BACKGROUND: Acute Toxoplasma gondii infection during pregnancy represents a risk for congenital disease, especially among women without previous exposure to infection. There is, however, a paucity of information about the epidemiology of T. gondii infection in pregnant women in Tanzania. This study aimed to determine the seroprevalence of T. gondii infection and associated demographic, clinical, and behavioral risk factors in pregnant women attending ante-natal clinic (ANC) at Kilimanjaro Christian Medical Center (KCMC), a referral medical center in Northern Tanzania. METHODS: A hospital-based cross-sectional study was carried out from 1 February to 30 April 2017. Data on maternal demographic characteristics, obstetric history, knowledge, and practices related to T. gondii infection were collected from 254 pregnant women attending antenatal care at KCMC. A sample of 4 mL of blood was collected from each participant and sera prepared from each sample. Serum samples were tested for the presence of specific T. gondii IgG and IgM antibodies by indirect Enzyme-Linked Immunosorbent Assay (ELISA). DNA was extracted from whole blood for polymerase chain reaction (PCR) testing, targeting the DNA sequence coding for the Internal Transcribed Spacer 1 (ITS1). RESULTS: The overall T. gondii seroprevalence, including both IgM- and IgG-positive individuals, was 44.5%. Of the 254 tested women, 102 and 23 were seropositive for T. gondii-specific IgG and IgM antibodies respectively and 113 individuals had antibodies of either or both classes. All IgM-positive samples were also tested by PCR, and all were negative. The majority (90%) of the women surveyed had never heard about toxoplasmosis. Consumption of raw vegetables [aOR = 0. 344; 95% CI 0.151-0.784; p = 0.011] and having regular contact with soil [aOR = 0.482; 95% CI 0.268-0.8681; p = 0.015] were both associated with T. gondii antibody status. Inverse relationships with probability of T. gondii exposure were observed, such that these practices were associated with reduced probability of antibody detection. CONCLUSION: Based on serology results, we report widespread exposure to T. gondii infection among pregnant women attending ANC in KCMC. The complex interaction of risk factors for T. gondii infection needs to be studied in larger longitudinal studies.
ABSTRACT
BACKGROUND: Plasmodium falciparum and Salmonella typhi are major causes of fever in the tropics. Although these infections are caused by different organisms and are transmitted via different mechanisms, they have similar epidemio-logic and clinical features. This study aimed to determine the prevalence of S. typhi and P. falciparum infections and their associations with fever at 2 sites in Northern Tanzania. METHODS: This was a community-based, cross-sectional study, conducted from February to June 2016, involving 128 randomly selected individuals, aged between 1 and 70 years. Sixty-three (49.2%) participants were recruited from Bondo Ward, Tanga Region, and 65 (50.8%) were recruited from Magugu Ward, Manyara Region. Blood samples were collected by venepuncture into sterile microtubes. Detection of pathogen DNA was achieved via a multiplex real-time polymerase chain reaction assay. Data analysis was done using Stata, version 14. Prevalence data were presented as numbers and percentages, and chi-square analysis was used to assess associations. P values of .05 or less were considered statistically significant. RESULTS: Of 128 participants, 31 (24.2%) and 17 (13.3%) tested positive for P. falciparum and S. typhi infection, respectively. Of the 63 participants from Bondo, 31 (49.2%) had P. falciparum parasitaemia. None of the participants from Magugu tested positive for Plasmodium parasitaemia. S. typhi bacteraemia was detected in 11 (17.5%) of 63 and 6 (9.2%) of 65 participants in Bondo and Magugu, respectively. P. falciparum-S. typhi coinfection was only detected in Bondo (n=6, 9.5%). Age was the only variable that showed a significant association with both P. falciparum and S. typhi infection; falling within the 5-to 9-year or 10-to 15-year age groups was associated with both infections (X2=2.1; P=.045). Among the 30 patients with Plasmodium parasitaemia, 7 (23.3%) had fever, whereas 2 (12.5%) of 16 patients infected by S. typhi had fever. P. falciparum infection (X2=12.4, P<.001) and P. falciparum-S. typhi coinfection (X2=5.5, P=.019) were significantly associated with fever, while S. typhi infection alone was not. CONCLUSION: S. typhi and P. falciparum were considerably prevalent in the area. One-third of the P. falciparum-S. typhi coinfected individuals in Bondo had fever. P. falciparum infection was an important contributor to febrile illness in Bondo. In the presence of coinfections with P. falciparum and S. typhi, the use of malaria rapid diagnostic tests should be emphasised to reduce irrational use of medications.
ABSTRACT
BACKGROUND: A major challenge to malaria vaccine development is identification of protective epitopes and respective protective immune responses. OBJECTIVE: To characterize naturally acquired Immunoglobulin G (IgG) responses to the synthetic peptide AS202.11, a malaria vaccine candidate. METHODOLOGY: This community based cross-sectional study enrolled 320 participants aged 1 year and above. Demographic information was recorded through interviews. Detection of P. falciparum infection was done by microscopy, malaria rapid diagnostic test, and polymerase chain reaction. ELISA was used to detect IgG antibody. Data was analyzed using STATA. RESULTS: The overall AS202.11 IgG seropositivity was 78.8% (73.9-82.9). Seropositivity by age categories was ≤12 years [74.3% (67.4-80.2)], 13-40 years [85.3% (76.5-91.1)], and >40 years [82.6% (68.7-91.1)]. Compared to the ≤ 12-year-old group, aORs for the other groups were 2.22 (1.14-4.32), p = 0.019, and 1.87 (0.81-4.35), p = 0.143, for the 13-40-year-old and >40-year-old groups, respectively. The 13-40-year-old group had more seropositive individuals compared to the ≤ 12-year-old group. CONCLUSION: We report a high degree of recognition of AS202.11 by IgG elicited by field P. falciparum strains, suggesting its close similarity to native P. falciparum antigens and possible suitability of the peptide as a future malaria vaccine candidate.
