• Parasites, Hosts and Diseases
• /
• 제59권2호
• /
• pp.113-119
• /
• 2021

The computer vision diagnostic approach currently generates several malaria diagnostic tools. It enhances the accessible and straightforward diagnostics that necessary for clinics and health centers in malaria-endemic areas. A new computer malaria diagnostics tool called the malaria scanner was used to investigate living malaria parasites with easy sample preparation, fast and user-friendly. The cultured Plasmodium parasites were used to confirm the sensitivity of this technique then compared to fluorescence-activated cell sorting (FACS) analysis and light microscopic examination. The measured percentage of parasitemia by the malaria scanner revealed higher precision than microscopy and was similar to FACS. The coefficients of variation of this technique were 1.2-6.7% for Plasmodium knowlesi and 0.3-4.8% for P. falciparum. It allowed determining parasitemia levels of 0.1% or higher, with coefficient of variation smaller than 10%. In terms of the precision range of parasitemia, both high and low ranges showed similar precision results. Pearson's correlation test was used to evaluate the correlation data coming from all methods. A strong correlation of measured parasitemia (r²=0.99, P<0.05) was observed between each method. The parasitemia analysis using this new diagnostic tool needs technical improvement, particularly in the differentiation of malaria species.

• Communications for Statistical Applications and Methods
• /
• 제21권6호
• /
• pp.487-500
• /
• 2014

A new method to calculate the transmittable prevalence of an epidemic disease is proposed based on a back-calculation formula. We calculated the probabilities of reactivation and of parasitemia as well as transmittable prevalence (the number of persons with parasitemia in the incubation period) of malaria in South Korea using incidence of 12 years(2001-2012). For this computation, a new probability function of transmittable condition is obtained. The probability of reactivation is estimated by the least squares method for the back-calculated longterm incubation period. The probability of parasitemia is calculated by a convolution of the survival function of the short-term incubation function and the probability of reactivation. Transmittable prevalence is computed by a convolution of the infected numbers and the probabilities of transmission. Confidence intervals are calculated using the parametric bootstrap method. The method proposed is applicable to other epidemic diseases in other countries where incidence and a long incubation period are available. We found the estimated transmittable prevalence in South Korea was concentrated in the summer with 276 cases on a peak at the $31^{st}$ week and with about a 60% reduction in the peak from the naive prevalence. The statistics of transmittable prevalence can be used for malaria prevention programs and to select blood transfusion donors.

• Parasites, Hosts and Diseases
• /
• 제53권3호
• /
• pp.265-270
• /
• 2015

Hemoglobinopathy and malaria are commonly found worldwide particularly in malaria endemic areas. Thalassemia, the alteration of globin chain synthesis, has been reported to confer resistance against malaria. The prevalence of thalassemia was investigated in 101 malaria patients with Plasmodium falciparum and Plasmodium vivax along the Thai-Myanmar border to examine protective effect of thalassemia against severe malaria. Hemoglobin typing was performed using low pressure liquid chromatography (LPLC) and ${\alpha}$-thalassemia was confirmed by multiplex PCR. Five types of thalassemia were observed in malaria patients. The 2 major types of thalassemia were Hb E (18.8%) and ${\alpha}$-thalassemia-2 (11.9%). There was no association between thalassemia hemoglobinopathy and malaria parasitemia, an indicator of malaria disease severity. Thalassemia had no significant association with P. vivax infection, but the parasitemia in patients with coexistence of P. vivax and thalassemia was about 2-3 times lower than those with coexistence of P. falciparum and thalassemia and malaria without thalassemia. Furthermore, the parasitemia of P. vivax in patients with coexistence of Hb E showed lower value than coexistence with other types of thalassemia and malaria without coexistence. Parasitemia, hemoglobin, and hematocrit values in patients with coexistence of thalassemia other than Hb E were significantly lower than those without coexistence of thalassemia. Furthermore, parasitemia with coexistence of Hb E were 2 times lower than those with coexistence of thalassemia other than Hb E. In conclusion, the results may, at least in part, support the protective effect of thalassemia on the development of hyperparasitemia and severe anemia in malaria patients.

• Parasites, Hosts and Diseases
• /
• 제47권4호
• /
• pp.409-412
• /
• 2009

In this experiment, the correlation between antigenemia and specific antibody responses in Toxoplasma gondii-infected rabbits was assessed. We injected 1,000 T. gondii tachyzoites (RH) subcutaneously into 5 rabbits. Parasitemia, circulating antigens, and IgM and IgG antibody titers in blood were tested by ELISA and immunoblot. For detection of parasitemia, mice were injected with blood from rabbits infected with T. gondii and mice died between days 2 and 10 post-infection (PI). Circulating antigens were detected early on day 2 PI, and the titers increased from day 4 PI and peaked on day 12 PI. Anti-Toxoplasma IgM antibody titers increased on day 6 PI and peaked on days 14-16 PI. IgG was detected from day 10 PI, and the titers increased continuously during the experiment. The antigenic protein patterns differed during the infection period, and the number of bands increased with ongoing infection by the immunoblot analysis. These result indicated that Toxoplasma circulating antigens during acute toxoplasmosis are closely related to the presence of parasites in blood. Also, the circulating antigen levels were closely correlated with IgM titers, but not with IgG titers. Therefore, co-detection of circulating antigens with IgM antibodies may improve the reliability of the diagnosis of acute toxoplasmosis.

• Parasites, Hosts and Diseases
• /
• 제57권2호
• /
• pp.117-125
• /
• 2019

Malarial infection induces tissue hypoxia in the host through destruction of red blood cells. Tissue hypoxia in malarial infection may increase the activity of $HIF1{\alpha}$ through an intracellular oxygen-sensing pathway. Activation of $HIF1{\alpha}$ may also induce vascular endothelial growth factor (VEGF) to trigger angiogenesis. To investigate whether malarial infection actually generates hypoxia-induced angiogenesis, we analyzed severity of hypoxia, the expression of hypoxia-related angiogenic factors, and numbers of blood vessels in various tissues infected with Plasmodium berghei. Infection in mice was performed by intraperitoneal injection of $2{\times}10^6$ parasitized red blood cells. After infection, we studied parasitemia and survival. We analyzed hypoxia, numbers of blood vessels, and expression of hypoxia-related angiogenic factors including VEGF and $HIF1{\alpha}$. We used Western blot, immunofluorescence, and immunohistochemistry to analyze various tissues from Plasmodium berghei-infected mice. In malaria-infected mice, parasitemia was increased over the duration of infection and directly associated with mortality rate. Expression of VEGF and $HIF1{\alpha}$ increased with the parasitemia in various tissues. Additionally, numbers of blood vessels significantly increased in each tissue type of the malaria-infected group compared to the uninfected control group. These results suggest that malarial infection in mice activates hypoxiainduced angiogenesis by stimulation of $HIF1{\alpha}$ and VEGF in various tissues.

• Parasites, Hosts and Diseases
• /
• 제30권3호
• /
• pp.177-182
• /
• 1992

Saimiri 원숭이 21마리와 Aotus 원숭이 12마리에게 Plasmedium falciparum Indochina CDC-1충주(원숭이 순응 충주)를 접종시킨 후 3주간 혈소판과 혈액치를 경시적으로 관찰하였던 바, 이들 원숭이 (Saimiri sciureus boliviensis와 Aotus nancymai karyotype-1)는 접종 14일 후에 최고의 기생률, 호중구감소증, 임파구증가증 그리고 심한 혈색소혈증과 섬유소원의 퇴행성 산물(FDP's)치의 증가를 수반한 섬한 혈소판 감소성 빈혈증이 관찰되었다. Aotus에 있어서는 평균혈색소량(MCH)과 평균혈구용적(MCV)치의 감소와 기생률의 증가를 가져왔으나, Saimiri에 있어서는 기생률이 상승함에 따라서 이들 혈액치는 유의적 차이로 상승하는 결과를 가져왔다. 일반적으로 이들 두 원숭이에 있어서 혈소판의 감소 증세와 최고 기생률을 14잎 째 나타낸 후 곧 정상 혈액치로 회복되는 소견이 관찰된다. 특히 혈소판의 변화에 있어서 Aotus 원숭이는 다른 혈액치의 변화 그리고 기생률과 깊 은 상관관계를 갖고 있었으나, Saimiri에 있어서는 상관관계를 유지하지 못하였다. 결론적으로 말라리아 연구시 Aotus 원숭이가 Saimiri 원숭이 보다 우수한 품종임과 말라리아 진단과정에 있어서 혈소판의 회복률과 재생은 말라리아의 감염시기 판정에 유용한 자료로서 활용될 수 있음을 관찰하였으며, 말라리아 병원성 판정에 대한 실험에 있어서 이들 두 종류 원숭이의 혈액치 변화 특이성을 보고하는 바이다.

• Parasites, Hosts and Diseases
• /
• 제61권1호
• /
• pp.42-52
• /
• 2023

The genus Babesia includes parasites that can induce human and animal babesiosis, which are common in tropical and subtropical regions of the world. The gut microbiota has not been examined in hamsters infected by Babesia duncani. Red blood cells infected with B. duncani were injected into hamsters through intraperitoneal route. To evaluate the changes in gut microbiota, DNAs were extracted from small intestinal contents, acquired from hamsters during disease development. Then, the V4 region of the 16S rRNA gene of bacteria was sequenced using the Illumina sequencing platform. Gut microbiota alternation and composition were assessed according to the sequencing data, which were clustered with >97.0% sequence similarity to create amplicon sequence variants (ASVs). Bacteroidetes and Firmicutes were made up of the major components of the gut microbiota in all samples. The abundance of Bacteroidetes elevated after B. duncani infection than the B. duncani-free group, while Firmicutes and Desulfobacterota declined. Alpha diversity analysis demonstrated that the shown ASVs were substantially decreased in the highest parasitemia group than B. duncani-free and lower parasitemia groups. Potential biomarkers were discovered by Linear discriminant analysis Effect Size (LEfSe) analysis, which demonstrated that several bacterial families (including Muribaculaceae, Desulfovibrionaceae, Oscillospiraceae, Helicobacteraceae, Clostridia UGG014, Desulfovibrionaceae, and Lachnospiraceae) were potential biomarkers in B. duncani-infected hamsters. This research demonstrated that B. duncani infectious can modify the gut microbiota of hamsters.

• 대한수의학회지
• /
• 제37권2호
• /
• pp.409-416
• /
• 1997

Bovine theileriosis caused by Theileria sergenti is the tick-borne intraery- throcytic piroplasmosis, that occurs in most regions of Korea. It results in severe economic losses on a farm caused by anemia, milk production loss, abortion and death. This study was undertaken to confirm the effects of the growth hormone and the insulin-like growth factor-I which are associated in the growth of cattle infected by T sergenti. The blood of one hundred and twenty ten-month Holstein was collected and the prepared blood smear was stained with acridine orange to investigate their parasitemia. And the hematological profiles were observed. According to the value of the hematocrit, they were categorized into four groups : Group 1 was under 20 percent, groups 2 and 3 were from over 21 to under 30 percent and from over 31 to under 35 percent and group 4 was over 36 percent. As the value of the hematocrit decreased, parasitemia(%) in erythrocytes was observed to increase(Y=-1.064X + 30.537, r=0.660). The amounts of the growth hormone and the insulin-like growth factor-I in the serum were measured by the radioimmunoassay. The growth hormone in serum of the group 1, group 2, group 3 and group 4 were observed as $0.238{\pm}0.043nmol/l$, $0.21{\pm}0.024nmol/l$, $0.366{\pm}0.035nmol/l$ and $0.646{\pm}0.223nmol/l$, respectively. The quantitative of the insulin-like growth factor-I in the same groups were observed also as $209.686{\pm}18.94ng/ml$, $250.9{\pm}12.609ng/ml$, $279.3{\pm}8.883ng/ml$ and $365.9{\pm}22.45ng/ml$, respectively. It can be concluded that the growth hormone and the insulin-like growth factor-I were observed to decrease in severe anemia due to theileriosis.

• Parasites, Hosts and Diseases
• /
• 제30권2호
• /
• pp.133-140
• /
• 1992

T. sergenti merozoite 수용성 항원을 T. sergenti 감염적혈구로부터 분리하고자 저삼투압액으로 용혈, 조직 분쇄기로 분쇄한 후에 고속 원심분리하여 수용성 항원을 얻었으며, SDS-PAGE와 Western blot의 방법으로 29, 34, 35 그리고 105 kD가 함유된 항원을 본 예방접종실험의 항원성 polypeptide로 정하였다. 본 수용성 항원(0.5 mg/ml)을 준비, Freund's adjunant를 이용하여 한우(5개월령)에 경피 접종하였으며, 다시 4주 후에 추가접종하였다. 추가접종 9주 후에 예방 접종군과 대조군에 동종의 냉동충주(5.6$\times$106RBC/dose, 40% 기생률)을 접종시킨 후에 적혈구용적비, 총적혈구수, 기생률, western biot에 의한 특이항체 그리고 간접형광항체(IFA) 등을 관찰하였던 바, 예방접종 후 18주(충 접종 6주 후)에 있어서 예방접종군의 IFA는 10,240이었으나, 대조군은 1,280이었다. 예방접종군에 있어서의 충접종 전후에 있어서의 총적혈구소와 적혈구웅적비는 유의적 차이 (p<0.05)를 나타내지 않았지만, 대조군에 있어서는 적혈구용적비와 총적혈구수에서 있어서 빈혈 소견을 관찰하였다 (p<0.05). 예방접종군의 충전종 후에 있어서의 western blot 반응에서는 29, 34, 35 그리고 105 kD polypeptide의 물질이 면역반응을 잘 나타내고 있어, 이들 polypeptide는 앞으로 vaccine 제조에 활용 가능성이 충분함을 예견할 수 있었다.

• Parasites, Hosts and Diseases
• /
• 제52권5호
• /
• pp.501-505
• /
• 2014

In recent years, rapid diagnostic tests (RDTs) have been widely used for malaria detection, primarily because of their simple operation, fast results, and straightforward interpretation. The Asan $EasyTest^{TM}$ Malaria Pf/Pan Ag is one of the most commonly used malaria RDTs in several countries, including Korea and India. In this study, we tested the diagnostic performance of this RDT in Uganda to evaluate its usefulness for field diagnosis of malaria in this country. Microscopic and PCR analyses, and the Asan $EasyTest^{TM}$ Malaria Pf/Pan Ag rapid diagnostic test, were performed on blood samples from 185 individuals with suspected malaria in several villages in Uganda. Compared to the microscopic analysis, the sensitivity of the RDT to detect malaria infection was 95.8% and 83.3% for Plasmodium falciparum and non-P. falciparum, respectively. Although the diagnostic sensitivity of the RDT decreased when parasitemia was ${\leq}500\;parasites/{\mu}l$, it showed 96.8% sensitivity (98.4% for P. falciparum and 93.8% for non-P. falciparum) in blood samples with parasitemia ${\geq}100\;parasites/{\mu}l$. The specificity of the RDT was 97.3% for P. falciparum and 97.3% for non-P. falciparum. These results collectively suggest that the accuracy of the Asan $EasyTest^{TM}$ Malaria Pf/Pan Ag makes it an effective point-of-care diagnostic tool for malaria in Uganda.