Comparative performance of microscopy, nested PCR, and real-time PCR for screening avian haemosporidian parasites in Afrotropical starlings (family Sturnidae)

Prevalence studies of avian haemosporidian parasites frequently use microscopy and the nested polymerase chain reaction (PCR) protocols for detecting infections. Newer PCR protocols to detect parasites are being developed, with the distinct advantage of reducing screening cost and time, as well as increasing efficiency and sensitivity. The detection ability of microscopy and nested PCR was compared against a real-time PCR (qPCR) protocol using genomic DNA extracted from 240 bird blood samples collected from three starling species (Cape Starling, the Greater Blue-eared Starling, and the Wattled Starling; family Sturnidae) in the Kruger national park, South Africa. All three protocols successfully detected avian haemosporidian parasites with the qPCR having a considerable edge against the other two methods. Fifteen unique cytochrome b lineages were identified of which seven were new lineages. Microscopy and nested PCR recorded similar prevalence (32.92% and 35.42% respectively). The qPCR protocol used here, although more sensitive (52.92% prevalence), is not able to differentiate between parasite genera but provides the opportunity to screen a large number of samples in large-scale studies within a specific region. This study recommends the development and adoption of new molecular protocols with increased sensitivity and accuracy in prevalence studies. Nevertheless, microscopy remains essential for the morphological description of parasites and for distinguishing between abortive and successful chronic infections. The PCR-based method displays the detection of the parasitic genome but does not reveal whether parasites have or will develop into a successful infection.

Association of interleukin-8 gene polymorphisms in HIV patients with opportunistic infections in Limpopo Province, South Africa

Opportunistic infections (OIs) are common among human immunodeficiency virus (HIV) patients; however, genetic susceptibility to these infections has not been studied. Recent studies have shown that interleukin-8 (IL-8) A/T genotype carriers are more susceptible to a variety of diseases. In this study, we showed the effects of IL-8 gene polymorphisms on OIs and symptoms such as sexually transmitted diseases (STDs), tuberculosis (TB), diarrhea, shortness of breath, weight loss, and viral load, in HIV and acquired immunodeficiency syndrome patients. Genomic DNA was purified from mouthwash samples collected from patients attending HIV centers in the Vhembe district. The IL-8 (-251) A/T locus was genotyped using allele-specific polymerase chain reaction followed by agarose gel electrophoresis. The results showed a weak association between the IL-8 AA genotype and OIs such as STDs (P = 0.143), diarrhea (P = 0.906), and TB (P = 0.762). Significant associations were found between the IL-8 AT genotype and weight loss (P = 0.019), shortness of breath (P = 0.043), and skin problems (P = 0.003). Low viral load was also found to be significantly associated with IL-8 AA genotype (P = 0.009). The present study suggests that different IL-8 genotypes are associated with resistance to various OIs. However, further studies using larger samples sizes are needed to confirm this hypothesis.

Interleukin-7 receptor gene polymorphism at +1237 locus and its effect on susceptibility to opportunistic infections among HIV and AIDS patients in Limpopo Province, South Africa

Over the past decade, an increasing number of studies have demonstrated correlations between host genetics and susceptibility to diseases. However, few studies have investigated the effects of host genetics on the occurrence of opportunistic infections among human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) patients. In the present study, the frequency of the interleukin (IL)-7Rα+1237 A/G single nucleotide polymorphisms was determined in relation to opportunistic infection occurrence among HIV and AIDS patients in the Vhembe District. Demographic, clinical, and socioeconomic status data were collected from patients using a structured questionnaire. Genomic DNA was extracted from mouthwash samples using the QIAmp Blood Mini Kit. Genotyping of the IL-7Rα+1237 gene was conducted using a sequence-specific polymerase chain reaction method. We found that the IL-7Rα+1237 genotype distribution in our study population differed from those in European populations with a predominance of the A/G genotype. Individuals carrying the A/G genotype primarily suffered from chest pain (χ(2) = 5.016, P = 0.025), while individuals carrying the G/G genotype were protected from chest pain but had a higher prevalence of sexually transmitted disease (23 vs 16.9%); however, the difference was not statistically significant (P = 0.435). Individuals carrying the A/A genotype were more susceptible to diarrhea (32 vs 13.6%) (P = 0.034). Our data will support gene therapy and may be used to modify the course of diseases among HIV patients as well as the general population. Further studies using larger populations are needed to confirm these hypotheses.

Distribution of CXCR2 +1208 T/C gene polymorphisms in relation to opportunistic infections among HIV-infected patients in Limpopo Province, South Africa

Interleukin 8 (IL-8) is a chemokine produced by macrophages and other cell types, including epithelial cells, and its receptor is CXCR2. IL-8 plays an important role in the initiation and amplification of inflammatory diseases, including opportunistic infections. With the advent of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome, opportunistic infections have become major health concerns. However, the role of host genetics on the occurrence of these infections has not been clearly defined. In this study, genomic DNA was extracted from 185 HIV-infected individuals in the Limpopo Province, South Africa. Allele-specific polymerase chain reaction was used to genotype the CXCR2 +1208 T/C gene. Genotypes CC, TT, and TC were associated with chest pains, frequent headaches, loss of weight, diarrhea, and loss of appetite among HIV patients. A significant association between the CC genotype and chest pains was found (P=0.035). The TC genotype was associated with loss of appetite (P=0.044) and chest pains (P=0.042). A weak association between diarrhea and the TT genotype was found (P=0.082). No association was observed between tuberculosis and the genotypes. Immunological characteristics, such as viral load and CD4 count, were not significantly associated with the genotypes. The results of the present study suggest that carriers of the TC genotype are more susceptible to chest pain, but that this genotype confers a protective effect against loss of appetite. The CC genotype was found to confer protection against chest pain but appeared to increase susceptibility to headaches. Further studies using larger samples are necessary to confirm these results.