89 research outputs found
An Overview of Tropical Diseases
No full textTropical diseases affect millions of people throughout the world and particularly in the developing countries. The millennium development goals had specifically targeted HIV/AIDS and Malaria for substantial reduction as well as Tuberculosis while many other tropical diseases have been neglected. The new sustainable development goals have not made such distinction and have targeted all diseases for elimination for the improvement of the quality of life of human beings on earth. The present book was developed to provide an update on issues relevant to the treatment of selected tropical diseases such as tuberculosis, malaria, leishmaniasis, schistosomiasis and ectoparasites such as chiggers which are widely distributed throughout the world. The control of these infections has been hampered by the development of drug resistance and the lack of the development of new and more effective drugs. The understanding of the biochemical processes underlying drug activity is therefore essential for the potential elimination of these infections
<i>Escherichia coli</i>
No full textEscherichia coli is a versatile organism and very diverse. Members of this species vary from very pathogenic agents causing different types of diseases including meningitis, gastroenteritis, and septicemia, just to cite a few, to harmless organisms living in the intestines of both humans and animals. E. coli has also been used as a model organism for most bacteria except a few. For this reason, its study provides a huge advantage and can help understand the mechanisms involved in different processes such as pathogenesis, environmental disinfection, nutrient utilization, antibiotic resistance, and diagnostic/detection methods, and these are indeed the topics discussed in this book. The book has been divided into four main sections representing the different facets of E. coli applications, which include disease, biotechnology, environmental engineering and innovative approaches to detection, and lastly its physiology and cell biology. Such processes can be applied to the study of other organisms as well considering the development of diversity; for example, many organisms are capable of horizontal gene transfer, which is capable of increasing the fitness of the bacterial organisms involved and has a great impact on the control of such bacterial organism
Molecular characterization of entamoeba histolytica tRNA genes
No full textM.Sc. (Microbiology)Department of MicrobiologyBACKGROUND: Entamoeba histolytica is a eukaryotic protozoan parasite responsible for the disease called amoebiasis. Amoebiasis is a major cause of morbidity and mortality in the developing world. It is well established that about 500 million people are infected worldwide, resulting in up to 100,000 deaths annually. It is not completely understood why some individuals once infected with E. histolytica, develop clinical amoebiasis while others remain asymptomatic. Very few studies have been conducted in order to determine the potential role of the parasite genomic features on the outcome of the infection. No studies have been done in South Africa to show how parasite genotypes play a role in determining the outcome of infection. Therefore, the present study determined the molecular characteristics of tRNA genes of E. histolytica in relation to the occurrence of diarrhea.
METHOD: In this study, patients were recruited from rural pnmary health care clinics in Giyani, Limpopo Province and private clinics in Pretoria, Gauteng Province. The participants were supplied with a consent form and their information was kept confidential. Diarrheal and non-diarrheal stool samples were collected. All the stool samples were observed under a light microscope for the presence of E. histolytica cysts and trophozoites. The Techlab E. histolytica II kit was used to detect the antigen against E. histolytica. Genomic DNA was extracted from 78 stool samples that were positive by ELISA using ZYMO RESEARCH fecal DNA mini Prep kit from inqaba biotech. A multiplex PCR protocol was used for the identification of E. histolytica. Specific primers for the different loci (NK, RR, AL, DA and STGA_D) of the tRNA genes of E. histolytica were used for genotyping. In this study, 15 stool samples from the 42 positive
samples identified by ELISA and confirmed by PCR were amplified for the NK locus using the tRNA specific primers NK-3 and NK-5. The genotyping as well as the data were analyzed using the Statistical Package for Social Sciences (SPSS for WINDOWS version 18.0) program in order to determine the potential implications of E. histolytica infection.
RESULTS: A total of 774 stool samples were collected and it was found that, out of 774 stool samples examined by wet mount microscopically 16.7% were infected with E. histolytica cysts and trophozoites. The TechLab ELISA based antigen detection kit specific only for E. histolytica in stool samples revealed that 10.1% were positive for E. histolytica. The highest prevalence of
E. histolytica was found in Pretoria with 10.5%, as compared to Giyani which was 5.4% and the difference was not statistically significant (X2= 1.491; P= 0.222). Entamoeba histolytica was more common in males (12%) than in females (8.4%), but the difference was not statistically significant (X2= 2.653; P= 0.103). Most of the participants who were infected were aged between 26-45 years with 21.2% followed by those who were in the age group 1-25 years with 16.8%. The least infected were of the age group 49-90 years with 8.2%. However, the difference was not statistically significant (X2= 3.341; P= 0.188). According to samples consistency, the highest prevalence was found in watery stool samples with 13.6%, followed by soft with 11.1% and the least was formed with 5.9%, but the difference was not statistically significant (X2= 5.781; P=
Forty-two samples showed positive for E. histolytica small-subunit rRNA gene. Nine (9) different banding patterns were obtained for NK locus. The ratio of the profile and the number of samples tested was therefore three profiles for every 5 samples. Two hundred base pairs was the most common band that occurred five times in different samples as compared to 150bp and
250bp that occurred twice. Other bands observed included 120bp, 300bp, 350bp, 500bp, 600bp and 750bp which occurred only once each. Out of the 42 positive samples identified by ELISA and confirmed by PCR the RR locus was amplified in 30 samples using the tRNA specific primers RR-3 and RR-5. This gave a success rate of 71%. The product sizes of 150, 200, 250, 300, 400,450, 500, 550, 600 and 750bp were obtained. It was observed that 150bp and 250bp occurred only once. A total of 16 profiles were obtained giving a ratio of 0.53.
Out of the 42 positive samples identified by ELISA and confirmed by PCR, the AL locus was amplified in 25 samples using the tRNA specific primers AL-3 and AL-5. This gave an amplification success of 59.5%. The product size of 150, 180 200, 220, 300, 350, 400 450, 500, 550, 600 and 1000bp were obtained. A total of 15 profiles were obtained for a ratio of 0.6. The band size of 200bp was seen in most of the samples, followed by 150, 180 220, 300, 350, 400,450, 500, 550, 600 and 1000bp. It was observed tr.at l 50bp and 550bp occurred only once.
Thirteen (31%) stool samples from the 42 positive samples identified by ELISA and confirmed by PCR were amplified for the DA locus using the tRNA specific primers DA-3 and DA-5. The product sizes of 150, 200, 280 300, 500 and 1200bp were obtained. One hundred and fifty base pair was seen in most of the samples, followed by 300 and 500bp bands. It was observed that bands of 200bp, 280bp, and l 200bp occurred only once.
ine (21%) stool samples from the 42 positive samples identified by ELISA and confirmed by PCR were amplified for the sTG -D locus using the tFNA specific primers STGA_D -3 and sTc - D -5. The product size of 150 180, 200, 220, 300, 350, 400,450, 500, 550, 600 and 1000bp were obtained. From the 9 samples that amplified for the sTGA_D locus, bands of 150, 200, 280 and
400bp was seen in most of the samples. It was observed that 100, 240, and 300bp occurred only once. All samples were from Pretoria.
CONCLUSION: The present study indicates that infection caused by E. histolytica was prevalent in diarrheal samples obtained from Pretoria. Entamoeba histolytica infection was more prevalent in males than in females, and in the age group of 26- 45 years. The possible cause of infection in the stools of patients in this study could possibly be due to various factors such as drinking water from unprotected source or by direct contact with infected animals. According to our results, icroscopy is a simple method and it should be combined with other methods such as ELI A and PCR for identification of the species to avoid false and/or insufficient diagnosis and treatment applications.
Loci K, RR, L, DA and STGA_D of t:ie tRNA genes identified in this study show promise as surrogate markers for prediction of infection outcome of Entamoeba histolytica. The findings of this study therefore suggest that further studies are needed to evaluate the prevalence heterogeneity and combination of virulence-related genes in E. histolytica infection as well as their association with diarrhea and non-diarrhea
Prevalence and molecular characterization of enteric viruses and their association with malnutrition in children less than two years old in the Vhembe Region of Limpopo Province, South Africa
No full textMSc (Microbiology)Department of Microbiolog
Detection of aeromonas species in relation to the occurrence of estrogens and testosterone in various water resources in Limpopo Province, South Africa and Lusaka, Zambia
No full textMSc (Microbiology)Department of MicrobiologyBackground: The occurrence of microorganisms and endocrine disrupting chemicals
(EDCs) in water poses a serious concern due to their effects on humans, animals and
environment. In recent years, EDCs have been increasingly reported in rivers that
receive large amounts of wastewater effluents. Of all the EDCs, natural and synthetic
hormones are among those that are recognized for their potential to mimic or interfere
with normal hormonal functions of humans and animals. The present study aimed at
assessing the occurrence of these hormones in relation to the molecular diversity of
Aeromonas and evaluating the resistance of Aeromonas to antibiotics as well as to
assess anti-bacterial activity of two selected traditional medicinal plants.
Methods: Wastewater, water and fish samples were collected from various sources
(rivers, wastewater treatment plants, taps, and dams) for the detection of hormones
and isolation of Aeromonas species. The analysis of hormones from various organs
of the fish and from water samples was conducted, after extraction using enzymelinked
immunosorbent assays (ELISA). Different types of hormones including Estriol,
Estradiol, Ethinylesradiol and Testosterone were detected, and their concentrations
determined. Aeromonas spp were isolated rom the samples using microbiological
methods and Conventional PCR was used for genotyping as well as for detection of
the beta-lactamase genes. Kirby-bauer method was used to determine the
susceptibility profiles of Aeromonas to different antibiotics. Microdilution assay was
used to determine the Anti-bacterial activity of the plant (Annoniceae and Zornia
milneana) extracts against Aeromonas species.
Results: A total of 144 samples were collected from 23 different locations in two
countries: South Africa and Zambia. These included wastewater and treated
wastewater, River water, fish and tap water. 17α-ethinylestradiol (EE2) was detected
in most of the samples (92.7%) with concentrations varying from 0.59 ng/ml to 65
ng/ml. The hormones were also detected from drinking water, with testosterone
detected at high concentrations of up to 140 ng/ml in tap water. Most sewage treatment
plants were not able to remove the EE2 from the wastewater as the concentration of
this hormone in the final effluent was almost always higher than that in the influent.
These homones were also detected in drinking water at high concentrations of up to
53.49 ng/ml in the tap water for EE2 and 1777 ng/ml for E2. The overall detection of
Aeromonas species in the samples was 84.5%. A. caviae was the most prevalent
species accounting for 73.6%, followed by A. veronii with 64.6%. The bacteria were
completely resistant to cefuroxime accounting for 100% resistance. Aeromonas
isolates also showed high resistance to trimethroprim (88.7% for A. hydrophila),
cefazolin (highest 97.8% for A. cavie), and ceftazidime (83.9% for A. sobria). TEM was
the most prevalent beta-lactamase gene with detection rate of 87%. All isolates lacked
the presence of the CTX-M3 gene. Also, wastewater had the highest prevalence of A.
veronni and A. caviae accounting for 87.5% and 82.5% respectively. Multiple antibiotic
resistance was also observed with the Aeromonas isolates being resistant to up to 11
antibiotics. High prevalence of 77.1% of Aeromonas hydrophila was observed in the
presence of ethinylestradiol (EE2). Aeromonas veronii and Aeromonas caviae were
the most predominant species in the presence of total estriol, A. veronii had a
prevalence of 57.1% and A. caviae had a prevalence of 52.8%. Aeromonas hydrophila
and Aeromonas caviae had the lower prevalence in the presence of hormones with
the percentages of 26.1% and 27.8% respectively. The methanol extracts of both
Zornia milneana and Annona species showed good activity against the Aeromonas
spp with the lowest MIC of 0.078 mg/ml. Ethyl acetate extracts were the least effective.
Conclusion: This study has shown high occurrence of steroid hormones in all types
of environmental samples tested. These included tap water, river water, wastewater
and fish both in Zambia and South Africa. Therefore, steroid hormones constitute and
important health problem in the Southern African Sub-Region. The incapacity of the
wastewater treatment plants to remove EE2 is an important problem that needs to be
tackled immediately. The prevalence of Aeromonas species is very high in our
environmental water as well as in drinking water, with the highest prevalence observed
in fish and wastewater. It was also revealed that there is relationship between steroid
hormones and Aeromonas species, with the hormones supporting the growth of
Aeromonas species. The presence of beta-lactamase genes which causes
Aeromonas to be resistant to antibiotics was also noted. Methanol extracts of Zornia
milneana and Annona spp were the most effective against Aeromonas spp and could
serve as primary sources for the isolation of lead compounds.NR
Molecular detection and identification of Cryptosporidium species isolated from human and animal sources in Limpopo and Gauteng Provinces
No full textMSc (Microbiology)Department of MicrobiologyBackground: Diarrheal diseases constitute an important problem among children but also
among HIV positive patients particularly in developing countries such as South Africa.
Cryptosporidium infect humans and has been shown to be an important cause of infection
among different types of animals. Because of its small size, Cryptosporidium can easily go
through the water purification system and can easily become a cause of an epidemic.
Previous studies have shown that Cryptosporidium is an important cause of diarrhea in
Limpopo Province. However, very few studies have been conducted on the genetic diversity
of these organisms in the region. Therefore, the aim of this study was to detect and identify
the genetic diversity of Cryptosporidium species from humans and animals in Giyani situated
in the northern part of South Africa and Pretoria situated in the central part of the country.
Methodology: A total of 560 samples were collected from human and animals and were all
screened by microscopy using modified Ziehl-Neelsen staining technique. All the samples
were tested by Enzyme-Linked Immunosorbent Assay (ELISA) using the Cryptosporidium II
kits from Techlab, Virginia, USA. Positive samples from microscopy and ELISA were
examined by different PCR protocols including conventional PCR for amplification of
Cryptosporidium oocyst wall protein (COWP) region; Real-time PCR employing SYBR
Green detection format for amplification of 18S rRNA region; Real-time PCR employing
Hydrolysis probes detection format for amplification of SSU rRNA region; Real-time PCR
specific for amplification of C. hominis region and C. parvum region. Positive samples from
real-time PCR that gave clear bands on gel electrophoresis were sent for sequencing. The
sequences were analysed using Staden package software to edit the nucleotides, Bioedit and
MEGA6 software were used to align sequences and draw phylogenetic trees. The SPSS
software was used for statistical analysis.
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Results: The overall prevalence of Cryptosporidium as detected by ELISA method from the
samples collected from humans was 41.2% (239/580). The prevalence was higher from the
rural area 73.0% (159/218) compared to the urban area 22.1% (80/362) and the difference
was statistically significant (χ2 = 145.1; p = 0.0001). Due to the limited amount of samples,
only 134 ELISA-positive samples were tested using real-time PCR. Of these samples, 35.8%
(48/134) tested positive. Of 48 real-time positive samples 25 were successfully sequenced
and two different species (C. hominis and C. muris) were identified. Of all the sequences
obtained, one (4.0%) was C. muris and 20 (80%) were C. hominis isolated from rural area,
whereas 16.0% (4/25) were also C. hominis isolated from samples obtained from urban area.
Cryptosporidium was not associated with diarrhea in the present study.
A total of 85 samples were collected from animals (52 from cattle and 33 from goats) and of
these 4 (4.7%) were positive by microscopy and ELISA. All these samples were non
diarrheal. Conventional PCR also detected a similar number. Of these 4 positive samples, 1
was from a male goat, while the 3 others were obtained from female adult goats.
Real-time PCR detected 56.5% (48/85) positive samples. Only 12 of the 85 animal samples
were diarrheal and of these 4 were positive for Cryptosporidium. The prevalence of
Cryptosporidium infection was higher 68.4% (13/19) in male animals compared to female
animals 53.0% (35/66). The prevalence rates in cattle and goats were 55.8% (29/52) and
60.6% (20/33) respectively.
Of 48 real-time positive samples from animals, 12 (25.0%) were successfully sequenced and
two species (C. parvum and C. andersoni) were identified. Of these 6 were from cattle and
the other 6 were from goats. Out of the 12 samples 10 (83%) were C. parvum while 2 (17%)
were C. andersoni. Of the two C. andersoni, one was from a goat and one was from a cow.
Of the 10 C. parvum, 5 were from goats and 5 were from cattle.
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In conclusion, microscopy remains the low sensitive tool for the detection of
Cryptosporidium while real time PCR appeared to be far much more sensitive by detecting
more samples than all the three other methods combined. Closer to the real time PCR was
ELISA that detected also more samples compared to conventional PCR and microscopy.
The present study identified C. muris from humans’ samples in our area for the first time.
However, C. hominis remains the dominant species that infects humans in our area.
Cryptosporidium species was mostly found in samples from asymptomatic individuals. In
animals, C. parvum was the most commonly isolated organism while C. andersoni was
identified in our region for the first time as well and occurred in both goats and cattle.
Populations in the affected areas need to be made aware of the infections so that care should
be taken to avoid the spread of infection in water sources or in immunocompromised
individuals
ANTIMICROBIAL ACTIVITY AND CYTOTOXICITY OF PTEROCARPUS ANGOLENSIS EXTRACTS AND COMPOUNDS AGAINST SELECTED BACTERIAL ORGANISMS AND ENTAMOEBA HISTOLYTICA
No full textPterocarpus angolensis also known as the bloodwood tree or Mutondo in Shi-Venda is well known to traditional doctors in the Venda region and commonly used. In the present study, extracts and compounds isolated from P. angolensis were prepared and tested against different bacterial organisms and Entamoeba histolytica. The cytotoxicity of the compounds was also determined using the MTT assay. The acetone extract was the most active against all the bacterial organisms tested with MIC varying between 0.0156 mg/ml against Staphylococcus aureus and 2 mg/ml against Enterobacter cloacae. Seven pure compounds were isolated and the structures of 5 were determined. The 5 isolated compounds included Phthalate and 4 derivatives of epicatechin. All the purified compounds were active against S. aureus as determined by bio-autography. Piperitenone (a compound isolated from Lippia javanica essential oil) and one compound out the eight obtained from P. angolensis appeared to be active against E. histolytica with IC50 of 25 ìg/ml and 100 ìg/ml respectively. The other P. angolensis compounds were not active up to the concentration of 400 ìg/ml tested. The compounds isolated from P. angolensis were more toxic than Piperitenone and their IC50 was found to be between 175 ìg/ml and 375 ìg/ml. In conclusion, the present study has demonstrated the presence of epichatechin and its derivatives from the stem bark of Pterocarpus angolensis and demonstrated their weak activities against E. histolytica. Further studies are needed to characterize the activity of the isolated compounds in the treatment of other diseases
EFFECTS OF COMBRETUM HEREROENSE AND CANTHIUM MUNDIANUM WATER EXTRACTS ON PRODUCTION AND EXPRESSION OF INTERLEUKIN-4
No full textBackground: Combretum hereroense and Canthium mundianum are two plants commonly used by traditional healers in the Northern region of Limpopo, South Africa for the treatment of diarrhea and inflammation. In the present study, the effects of their water extracts on the production and expression of interleukin-4 by peripheral blood mononuclear cells (PBMC’S) from HIV positive and negative individuals was evaluated.Materials and methods: Blood samples were collected from both HIV positive and HIV negative volunteers and were used for the purification of Peripheral blood mononuclear cells (PBMC). The PBMCs were cultured together with the water extracts after activation with phytohemagglutinin (PHA) for three days. Solid-phase sandwich ELISA (MABTECH) kit was used to detect IL-4 on un-stimulated and stimulated PBMC’S with phytohemaglutinin (PHA) and plant extracts, followed by the isolation of RNA using RNAesy Qiagen mini kit from the cells. Reverse transcriptase real time PCR was used to evaluate IL-4 gene expression by the cells.Results: Combretum hereroense showed higher production of IL-4 at three different concentrations and a significant expression of mRNA with 4-fold amplification increase at 300μg/ml and 2-fold amplification increase at 20μg/ml. Canthium mundianum also showed increased production of IL-4 at 300μg/ml, but inhibited its production at 20μg/ml. Both extracts showed no expression at 50μg/ml. The response of the PBMCs from HIV negative individuals was more pronounced than that of HIV positive individuals who mostly increased production of IL4 at smaller concentrations unlike their HIV negative counterparts. Although in vitro studies do not necessarily predict in vivo outcomes, the plant extracts modulated the immune system by enhancing the production and expression of IL-4 in both HIV- and HIV+ individuals at different concentrations.Conclusions: For the first time we have shown that the immunomodulatory effect of medicinal plants may depend on the clinical status of the individual. The present study revealed that the effect of the water extracts from the two plants on IL-4 expression and production is dependent on the microbiological state of the individual and is dose dependent. Further studies are needed to identify the active components in the extracts and also characterize the patients further for a better understanding of the mechanisms of action of these extracts.Keywords: interleukin-4, peripheral mononuclear cells, HIV, ELISA, gene expressio
Prevalence of Toxoplasma gondii IgG and IgM and associated risk factors among HIV-positive and HIV-negative patients in Vhembe district of South Africa
No full textBackground: Toxoplasma gondii is a zoonotic parasite that has arisen as an important opportunistic infection that causes morbidity and mortality especially in HIV positive patients. This study was carried out to determine the sero-prevalence of T. gondii (IgG and IgM) and the associated risk factors among HIV positive and negative patients in Northern South Africa.Materials and Methods: The study was conducted in the Vhembe District in Limpopo province from April 2012 to January 2013. A well-structured questionnaire was used to collect socio-demographic information and possible risk factor information on toxoplasmosis from participants. A total of 161 blood samples of both HIV positive and negative patients visiting the local clinics in the Vhembe district were collected. Serum samples were tested for IgG and IgM against T. gondii using commercially available ELISA protocol.Results: The prevalence of T. gondii IgG was 31.7% while that of T. gondii IgM was 4.9%. The prevalence of T. gondii IgG was higher in HIV positive patients (38%) compared to 16.7% among HIV negative patients (p=0.001). Toxoplasma gondii IgG antibodies were more common in patients who were not taking ARV’s (46.2%) compared to those who were taking ARV’s (35.2%) (P<0.001).Conclusions: The present study has shown a high prevalence of T. gondii (IgG) among patients attending different HIV clinics in the Vhembe district with no current infections among pregnant women. In addition to the sero-positive status of the patient to HIV, other significant risk factors for toxoplasmosis included high viral load, non-adherence to ARV therapy and age (>25 years).Keywords: ELISA, HIV, Toxoplasma gondii, Sero-prevalence, Opportunistic infections
Venda Study Area
No full textThis is a Google Earth file with additional geographic information for the randomized controlled study on the effect of ceramic water filter and silver-impregnated porous ceramic water treatment (MadiDrop) on child health.
This is a part of a study reported in a manuscript by: Joshua N. Edokpayi, Elizabeth T. Rogawski, David M. Kahler, Courtney Hill, Catherine Reynolds, Emanuel Nyathi, James A. Smith, John O. Odiyo, Amidou Samie, Pascal Bessong, Rebecca Dillingham.
The authors acknowledge the tireless work of the community field workers who installed interventions and collected all of the survey data. The authors also acknowledge A. Gaylord, N. Khuliso, S. Mammburu, K. McCain and E. Stinger, who performed much of the water quality analysis and T. Singh, who supported the laboratory analysis for inorganic materials
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