Browsing by Author "Gwakisa, Paul"

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Haptoglobin gene polymorphism influences the effect of malaria infection on host haptoglobin plasma level but not susceptibility to the disease
(2013-02) Alfred, Benigni; Gwakisa, Paul
A cohort of 344 children aged less than five years were followed for one year to establish the relationship between haptoglobin genotype, haptoglobin plasma level and malaria infection and susceptibility. Haptoglobin genotyping was undertaken using PCR, with plasma haptoglobin levels measured using indirect ELISA. The number of children carrying the genotypes Hp 1-1 , Hp 1-2 and Hp 2-2 were 85, 171 and 88, respectively. The state of malaria infection was assessed using standard microscopy method to detect parasitemia. Higher plasma haptoglobin level tended to be associated with negative parasitemia (P=0.01). During malaria infection, haptoglobin level decreased in all individuals and, the decrease significantly varied by genotype, whereby the decrease was greater in Hp 2-2 individuals than the other genotypes. A longitudinal examination of blood smears revealed a slightly higher proportion of children carrying the Hp 2-2 genotype (12.4%) to be positive for malaria, as compared to children with the genotype Hp 1-1 (11.7%) and Hp 1-2 (11.6%). The present study has demonstrated that malaria infection in children affects the haptoglobin plasma level and the effect is influenced by haptoglobin genotype. The study has also revealed a limited influence of haptoglobin genotype to malaria infection and disease development.
Malaria prevalence in asymptomatic and symptomatic children in Kiwangwa, Bagamoyo district, Tanzania
(Malaria Journal, 2017) Sumari, Deborah; Mwingira, Felista; Selemani, Majige; Mugasa, Joseph; Mugittu, Kefas; Gwakisa, Paul
Malaria prevalence continues to decline across sub-Saharan Africa as a result of various intervention strategies. However, the diseases still poses a public health concern in the region. While symptomatic malaria is recog- nized and treated, asymptomatic infections become increasingly important for interrupting transmission. A cross-sec- tional survey was conducted to assess malaria prevalence in symptomatic and asymptomatic children in Kiwangwa ward in Bagamoyo District in Tanzania. Methods: Four hundred school-aged children in Kiwanga ward were recruited in the study; 200 from Kiwangwa dispensary and 200 from nearby schools. Primary health parameters were examined and blood samples collected and examined for Plasmodium falciparum prevalence using rapid diagnostic test (RDT), light microscopy (LM) and reverse transcription quantitative PCR (RT-qPCR) targeting transcripts of A-type 18s rRNA of P. falciparum. Gametocytes were detected by LM and RT-qPCR targeting transcripts of gametocyte specific marker, Pfs25. Results: Overall P. falciparum prevalence was 73.3, 40.8 and 36.3% by RT-qPCR, RDT and LM in the study area, respec- tively (P < 0.001). As expected symptomatic children had a significantly higher prevalence of 89, 67.5 and 64.5% by qPCR, RDT and LM, compared to 57.5, 14 and 8% in the asymptomatic group, respectively. However, gametocyte prevalence in asymptomatic individuals was higher by both LM (2%) and qPCR (14%) than in symptomatic individuals LM (0.5%) and qPCR (3%). Conclusions: A substantial difference in prevalence of symptomatic and asymptomatic infections observed in Kiwangwa ward underpins the use of molecular tools in malaria surveillance aiming at estimating prevalence and transmission. Notably, the higher gametocytaemia observed in asymptomatic children indicates the reservoir infec- tions and points to the need for detection and treatment of both asymptomatic and symptomatic malaria.
Species and gender differentiation between and among domestic and wild animals using mitochondrial and sex-linked DNA markers
(2005-11) Malisa, Allen L; Balthazary, Sakurani; Wasser, Sam; Mutayoba, Benezeth; Gwakisa, Paul
In many African countries accurate and reliable identification of poached wildlife products like carcasses or meat presents a big problem when morphological characters such as skin hair or bones are missing. We describe a molecular based approach that has a potential of serving as a forensic tool in game meat identification in Africa. A mitochondial DNA marker (mt700) and one restriction enzyme, Rsa1 were used in the PCR-RFLP species identification of game meat obtained from two National Parks in Tanzania. Species-specific reference DNA fragment patterns were obtained using fresh meat from ten wildlife and four domesticated species. All species except the zebra, produced unique monomorphic RFLP patterns. Collectively, these patterns demonstrate the potential ability of genetic techniques for discriminating between and among wildlife and domestic species. The reference PCR-RFLP fragments enabled species identification of about 79% of unknown meat samples. In addition, sex was also assigned to all of the samples following successful amplification of gender-specific, SRY and ZFY/X, chromosomal domains. Although the present study has been conducted on a limited range both in numbers and genetic diversity of wildlife species present in Africa, the results demonstrate the potential usefulness of the DNA approach in wildlife forensics in the continent.
A study of rift valley fever virus in Morogoro and Arusha regions of Tanzania - serology and farmers’ perceptions
(Taylor & Francis Group, 2015-11-18) Wensman, Jonas J; Lindahl, Johanna; Wachtmeister, Nica; Torsson, Emeli; Gwakisa, Paul; Kasanga, Christopher; Misinzo, Gerald
Introduction: Rift Valley fever (RVF) is a zoonosis primarily affecting ruminants, resulting in epidemic abortions, fever, nasal and ocular discharges, haemorrhagic diarrhoea, and a high mortality rate among young animals. Rift Valley fever virus (RVFV) is an arthropod-borne RNA virus occurring in epizootic periods associated with heavy rainfall. The last outbreak of RVF in Tanzania was in 2006 2007, resulting in severe economic losses and impaired food security due to greater number of deaths of livestock. The aim of this study was to investigate the presence of antibodies against RVFV in sheep and goats in two different regions of Tanzania during an inter-epidemic period (IEP). In addition, the perception of important diseases among livestock keepers was assessed. Material and methods: A cross-sectional serological survey was conducted in three purposively selected districts in Arusha and Morogoro regions of Tanzania. Serum samples from 354 sheep and goats were analysed in a commercial RVFV competitive ELISA. At the sampling missions, a questionnaire was used to estimate the socio-economic impact of infectious diseases. Results and discussion: In total, 8.2% of the analysed samples were seropositive to RVF, and most seropositive animals were younger than 7 years, indicating a continuous circulation of RVFV in the two regions. None of the livestock keepers mentioned RVF as an important livestock disease. Conclusions: This study confirms that RVFV is circulating at low levels in small ruminants during IEPs. In spite of recurring RVF outbreaks in Tanzania, livestock keepers seem to have a low awareness of the disease, making them poorly prepared and thus more vulnerable to future RVF outbreaks.