THE DIAGNOSIS OF HUMAN OPISTHORCHIASIS

Abstract. Opisthorchiasis viverrini is a liver fluke infection causing a serious public health problem in Thailand, Lao PDR, Cambodia, and South Vietnam because it acts as a strong promoter of cholangiocarcinoma. The diagnosis of human opisthorchiasis is based on four approaches: clinical manifestations, parasitological, molecular biological, and immunological methods. These methods have advantages and disadvantages. Clinical manifestations of the patients are practically indistinguishable from those of other liver diseases. The features of the O. viverrini eggs are, by light microscopy, difficult to differentiate from those of other minute intestinal flukes' eggs. Polymerase chain reaction (PCR) is very complicated, needs special and expensive apparatus, and is time-consuming; it is, however, highly sensitive and specific. Immunological testing is the method of choice: the techniques are applicable to both routine laboratory work and field or epidemiological studies. Of these tests, enzyme-linked immunosorbent assay (ELISA) and immunoelectrotransfer blot assay are often used for the detection of O. viverrini-specific antigens (coproantigens) and antibodies (IgM, IgG, IgA, or IgE). Monoclonal antibodies are prepared to detect coproantigens, while the crude somatic and excretory-secretory antigens from the adult worms, metacercariae, eggs, and snail intermediate hosts are prepared in order to detect antibodies in sera. To eliminate the cross reactions between parasites, the appropriate amount, type, and efficacy of antigens or antibodies preparation should be considered. In this paper, the advantages and disadvantages of the four diagnostic methods are discussed

Open Access Prevalence of antifolate resistance mutations in Plasmodium falciparum isolates in Afghanistan

Background: Artesunate plus sulphadoxine-pyrimethamine (AS+SP) is now first-line treatment for Plasmodium falciparum infection in several south Asian countries, including Afghanistan. Molecular studies provide a sensitive means to investigate the current state of drug susceptibility to the SP component, and can also provide information on the likely efficacy of other potential forms of artemisinin-combination therapy. Methods: During the years 2007 to 2010, 120 blood spots from patients with P. falciparum malaria were obtained in four provinces of Afghanistan. PCR-based methods were used to detect drug-resistance mutations in dhfr, dhps, pfcrt and pfmdr1, as well as to determine copy number of pfmdr1. Results: The majority (95.5%) of infections had a double mutation in the dhfr gene (C59R, S108N); no mutations at dhfr positions 16, 51 or 164 were seen. Most isolates were wild type across the dhps gene, but five isolates from the provinces of Kunar and Nangarhar in eastern Afghanistan had the triple mutation A437G / K540E / A581G; all five cases were successfully treated with three receiving AS+SP and two receiving dihydroartemisinin-piperaquine. All isolates showed the pfcrt SVNMT chloroquine resistance haplotype. Five of 79 isolates had the pfmdr1 N86Y mutation, while 52 had pfmdr1 Y184F; positions 1034, 1042 and 1246 were wild type in all isolates. The pfmdr1 gene was not amplified in any sample

Protective effect of Mediterranean-type glucose-6-phosphate dehydrogenase deficiency against Plasmodium vivax malaria

X-linked glucose-6-phosphate dehydrogenase (G6PD) deficiency is the most common human enzymopathy. The severe Mediterranean variant (G6PD Med) found across Europe and Asia is thought to confer protection against malaria, but its effect is unclear. We fitted a Bayesian statistical model to observed G6PD Med allele frequencies in 999 Pashtun patients presenting with acute Plasmodium vivax malaria and 1408 population controls. G6PD Med was associated with reductions in symptomatic P. vivax malaria incidence of 76% (95% credible interval [CI], 58-88) in hemizygous males and homozygous females combined and 55% (95% CI, 38-68) in heterozygous females. Unless there is very large population stratification within the Pashtun (confounding these results), the G6PD Med genotype confers a very large and gene-dose proportional protective effect against acute vivax malaria. The proportion of patients with vivax malaria at risk of haemolysis following 8-aminoquinoline radical cure is substantially overestimated by studies measuring G6PD deficiency prevalence in healthy subjects

Number of individuals with the 563C>T mutation among 713 male individuals studied.

<p>The total number of individuals in each province/ethnicity grouping is presented as denominator (zero indicates that there were no individuals present in a given category).</p

Allele frequencies at 1311C>T marker in individuals carrying 563C>T mutation in southwest Asia.

<p>Data are derived from published studies of individuals (expressed as chromosomes) and this study. Countries of study and references are as follows: 1 = Palestine <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Sirdah1" target="_blank">[25]</a>, 2 = Saudi Arabia <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-KurdiHaidar1" target="_blank">[18]</a>, 3 = Iraq (Kurds) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-AlAllawi1" target="_blank">[26]</a>, 4 = Iraq (Baghdad) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-AlMusawi1" target="_blank">[27]</a>, 5 = Kuwait <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Samilchuk1" target="_blank">[17]</a>, 6 = Iran (Kurds) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Rahimi1" target="_blank">[28]</a>, 7 = Afghanistan (this study), 8 = Pakistan (northwest) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Saha2" target="_blank">[10]</a>, 9 = Pakistan (Karachi) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Moiz2" target="_blank">[30]</a>, 10 and 11 = India (Bombay) <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Chalvam1" target="_blank">[29]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Sukumar1" target="_blank">[31]</a>, 12 = Malaysia <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Ainoon1" target="_blank">[6]</a>.</p

Location, ethnicity and number of Mediterranean variants for the individuals studied.

<p>Black circles placed within the relevant segment represent individuals of a particular ethnic group with the 563C>T Mediterranean mutation. The number of individuals sampled in each province is shown next to the province name.</p

Frequency of 1311C>T/IVSXI C93T haplotypes according to allele at 563C>T (Mediterranean).

<p>*Includes 2 individuals with a novel synonymous 1398C>T mutation.</p

Haplotypes of 1311C>T and IVSXI C93T in G6PD-normal individuals.

<p>Data are expressed as total chromosomes and are derived from the 1000 genomes project <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Genomes1" target="_blank">[23]</a>, one published dataset from India <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0088605#pone.0088605-Sarkar1" target="_blank">[24]</a>(INDIA) and this study (AFG). Population abbreviations: ASW, people with African ancestry in Southwest United States; CEU, Utah residents with ancestry from Northern and Western Europe; CHB, Han Chinese in Beijing, China; CHS, Han Chinese South, China; CLM, Colombians in Medellin, Colombia; FIN, Finnish in Finland; GBR, British from England and Scotland, UK; IBS, Iberian populations in Spain; LWK, Luhya in Webuye, Kenya; JPT, Japanese in Tokyo, Japan; MXL, people with Mexican ancestry in Los Angeles, California; PUR, Puerto Ricans in Puerto Rico; TSI, Toscani in Italia; YRI, Yoruba in Ibadan, Nigeria.</p

G6PD molecular markers examined in the study.

<p>Numbers refer to the short isoform version of G6PD. *Commonly referred to as T93C, but correctly annotated as C93T in NCBI dbSNP, consistent with 1000 Genomes and <i>Pan</i> spp. data. This mutation could also be formally referred to as c.1365-13C>T.</p