ResearchPad - parasitology https://www.researchpad.co Default RSS Feed en-us © 2020 Newgen KnowledgeWorks <![CDATA[ICOS signaling promotes a secondary humoral response after re-challenge with <i>Plasmodium chabaudi chabaudi</i> AS]]> https://www.researchpad.co/article/elastic_article_7745 Malaria, which is caused by the protozoan parasite Plasmodium, remains a major global health problem, as over 400,000 people die from this disease every year. Further understanding of the mechanisms that contribute to protective immunity against this parasite will serve to promote the development of an effective vaccine. Here, we describe the importance of the co-stimulatory molecule ICOS during secondary infection with the rodent parasite Plasmodium chabaudi chabaudi AS. We show that ICOS promotes the expansion of memory T cells, their acquisition of a secondary follicular helper T (Tfh) cell phenotype, and their ability to provide help to MBCs after reinfection. While ICOS deficient mice control the initial parasite load after re-challenge, the absence of ICOS leads to higher relapsing parasitemia compared to wild-type mice. We establish that the lack of expansion of effector cells with a Tfh cell phenotype in Icos-/- mice prevents germinal center formation after secondary infection. Thus, we show that ICOS signaling in T cells promotes an effective memory T cell response and suggests that the enhancement of this co-stimulatory pathway during vaccination may enhance protective immunity to blood-stage Plasmodium infection.

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<![CDATA[Suggestions to Prepare for the Second Epidemic of COVID-19 in Korea]]> https://www.researchpad.co/article/elastic_article_8428 <![CDATA[Transcriptomic changes across the life cycle of <i>Trypanosoma cruzi II</i>]]> https://www.researchpad.co/article/elastic_article_8327 Trypanosoma cruzi is a flagellated protozoan that causes Chagas disease; it presents a complex life cycle comprising four morphological stages: epimastigote (EP), metacyclic trypomastigote (MT), cell-derived trypomastigote (CDT) and amastigote (AM). Previous transcriptomic studies on three stages (EPs, CDTs and AMs) have demonstrated differences in gene expressions among them; however, to the best of our knowledge, no studies have reported on gene expressions in MTs. Therefore, the present study compared differentially expressed genes (DEGs), and signaling pathway reconstruction in EPs, MTs, AMs and CDTs. The results revealed differences in gene expressions in the stages evaluated; these differences were greater between MTs and AMs-PTs. The signaling pathway that presented the highest number of DEGs in all the stages was associated with ribosomes protein profiles, whereas the other related pathways activated were processes related to energy metabolism from glucose, amino acid metabolism, or RNA regulation. However, the role of autophagy in the entire life cycle of T. cruzi and the presence of processes such as meiosis and homologous recombination in MTs (where the expressions of SPO11 and Rad51 plays a role) are crucial. These findings represent an important step towards the full understanding of the molecular basis during the life cycle of T. cruzi.

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<![CDATA[The common gallinule, <i>Gallinula galeata</i> (Aves: Gruiformes: Rallidae), as a new host for <i>Eimeria paludosa</i> (Apicomplexa: Eimeriidae) in Mexico]]> https://www.researchpad.co/article/N14c03c80-9ea9-416f-8440-f227e22660fa Up to now, four coccidian species have been identified in Rallidae (Aves: Gruiformes): Eimeria mongolica, E. alakuli, E. paludosa and E. porphyrulae. Here, we described an Eimeria species, E. paludosa, from a common gallinule (Gallinula galeata) in Mexico. Oocysts were ovoid and wall pitted single-layered. A prominent micropyle was present, the oocyst residuum absent and the polar granule was present. On histological examination of tissues, endogenous stages (meronts, microgametocytes and macrogametocytes) were seen in the epithelial cells of the small intestine (upper and lower intestine). In addition to a new locality, this is the first description of E. paludosa from G. galeata and is the third description of a coccidian infecting Rallidae in the Americas.

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<![CDATA[Detection of antibodies against <i>Toxoplasma gondii</i> in cats using an immunochromatographic test based on GRA7 antigen]]> https://www.researchpad.co/article/N6d123a15-f3f0-43cd-9980-6c9706fff684 Toxoplasmosis, caused by Toxoplasma gondii, is one of the most common parasitic diseases worldwide. The GRA7 of T. gondii (TgGRA7) is an essential component of the parasitophorous vacuole (PV) and PV membrane surrounding the tachyzoites and the cyst wall of the bradyzoites. While it has been widely employed as antigen for ELISA, there is only one study that has reported its potential as antigen for immunochromatographic test (ICT) in pigs. There is no study yet documenting its potential for ICT serodiagnosis of T. gondii infection in cats. In this study, we assessed the efficacy of an ICT using TgGRA7 in the detection of Toxoplasma infections in 100 cats and compared the results with iELISAs using TgGRA7 and lysate antigens of T. gondii strains, RH, PLK, and VEG. Our results revealed that TgGRA7-ICT is a reliable test for the diagnosis of anti-T. gondii antibodies in cats, producing comparable results as conventional serological methods. This study is the first report on the use of TgGRA7 as ICT antigen for the serodiagnosis of T. gondii infection in cats.

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<![CDATA[First Pediatric Case of Coronavirus Disease 2019 in Korea]]> https://www.researchpad.co/article/N2d71daac-6070-4654-b25c-782c75eb42ce

The large outbreak of coronavirus disease 2019 (COVID-19) that started in Wuhan, China has now spread to many countries worldwide. Current epidemiologic knowledge suggests that relatively few cases are seen among children, which limits opportunities to address pediatric specific issues on infection control and the children's contribution to viral spread in the community. Here, we report the first pediatric case of COVID-19 in Korea. The 10-year-old girl was a close contact of her uncle and her mother who were confirmed to have COVID-19. In this report, we present mild clinical course of her pneumonia that did not require antiviral treatment and serial viral test results from multiple specimens. Lastly, we raise concerns on the optimal strategy of self-quarantine and patient care in a negative isolation room for children.

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<![CDATA[Are We Ready for Coronavirus Disease 2019 Arriving at Schools?]]> https://www.researchpad.co/article/N37ad11c7-fbe3-4414-a6e0-df69b05bc806 ]]> <![CDATA[Drive-Through Screening Center for COVID-19: a Safe and Efficient Screening System against Massive Community Outbreak]]> https://www.researchpad.co/article/Nae1aad93-1250-4bf1-9782-17b1e3d5bcd5

As the coronavirus disease 2019 (COVID-19) outbreak is ongoing, the number of individuals to be tested for COVID-19 is rapidly increasing. For safe and efficient screening for COVID-19, drive-through (DT) screening centers have been designed and implemented in Korea. Herein, we present the overall concept, advantages, and limitations of the COVID-19 DT screening centers. The steps of the DT centers include registration, examination, specimen collection, and instructions. The entire service takes about 10 minutes for one testee without leaving his or her cars. Increased testing capacity over 100 tests per day and prevention of cross-infection between testees in the waiting space are the major advantages, while protection of staff from the outdoor atmosphere is challenging. It could be implemented in other countries to cope with the global COVID-19 outbreak and transformed according to their own situations.

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<![CDATA[Clinical Score System to Differentiate Severe Fever with Thrombocytopenia Syndrome Patients from Patients with Scrub Typhus or Hemorrhagic Fever with Renal Syndrome in Korea]]> https://www.researchpad.co/article/N37f1b837-2e40-4fdc-bb1b-5cbf97b889e8

Background

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease with high mortality in East Asia. This study aimed to develop, for primary care providers, a prediction score using initial symptoms and basic laboratory blood tests to differentiate between SFTS and other endemic zoonoses in Korea.

Methods

Patients aged ≥ 18 years diagnosed with endemic zoonoses during a 3-year period (between January 2015 and December 2017) were retrospectively enrolled from 4 tertiary university hospitals. A prediction score was built based on multivariate logistic regression analyses.

Results

Of 84 patients, 35 with SFTS and 49 with other endemic zoonoses were enrolled. In multivariate logistic regression analysis, independent predictors of SFTS included neurologic symptoms (odds ratio [OR], 12.915; 95% confidence interval [CI], 2.173–76.747), diarrhea (OR, 10.306; 95% CI, 1.588–66.895), leukopenia (< 4,000/mm3) (OR, 19.400; 95% CI, 3.290–114.408), and normal C-reactive protein (< 0.5 mg/dL) (OR, 24.739; 95% CI, 1.812–337.742). We set up a prediction score by assigning one point to each of these four predictors. A score of ≥ 2 had 82.9% sensitivity (95% CI, 71.7%–87.5%) and 95.9% specificity (95% CI, 88.0%–99.2%). The area under the curve of the clinical prediction score was 0.950 (95% CI, 0.903–0.997).

Conclusion

This study finding suggests a simple and useful scoring system to predict SFTS in patients with endemic zoonoses. We expect this strategic approach to facilitate early differentiation of SFTS from other endemic zoonoses, especially by primary care providers, and to improve the clinical outcomes.

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<![CDATA[Potential Hazards of Concern in the Walk-Through Screening System for the Corona Virus Disease 2019 from the Perspective of Infection Preventionists]]> https://www.researchpad.co/article/Ne5961423-4fe7-4d72-baa6-1fc2f305c3e0 ]]> <![CDATA[A Brief Telephone Severity Scoring System and Therapeutic Living Centers Solved Acute Hospital-Bed Shortage during the COVID-19 Outbreak in Daegu, Korea]]> https://www.researchpad.co/article/N2759f40e-dea8-4b14-9b5c-577601759b6b

With the epidemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2, the number of infected patients was rapidly increasing in Daegu, Korea. With a maximum of 741 new patients per day in the city as of February 29, 2020, hospital-bed shortage was a great challenge to the local healthcare system. We developed and applied a remote brief severity scoring system, administered by telephone for assigning priority for hospitalization and arranging for facility isolation (“therapeutic living centers”) for the patients starting on February 29, 2020. Fifteen centers were operated for the 3,033 admissions to the COVID-19 therapeutic living centers. Only 81 cases (2.67%) were transferred to hospitals after facility isolation. We think that this brief severity scoring system for COVID-19 worked safely to solve the hospital-bed shortage. Telephone scoring of the severity of disease and therapeutic living centers could be very useful in overcoming the shortage of hospital-beds that occurs during outbreaks of infectious diseases.

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<![CDATA[Walk-Through Screening Center for COVID-19: an Accessible and Efficient Screening System in a Pandemic Situation]]> https://www.researchpad.co/article/Nb874380b-408a-4305-91bf-5a42e508e52c

With the ongoing novel coronavirus disease 2019 (COVID-19) pandemic, the number of individuals that need to be tested for COVID-19 has been rapidly increasing. A walk-through (WT) screening center using negative pressure booths that is inspired by the biosafety cabinet has been designed and implemented in Korea for easy screening of COVID-19 and for safe and efficient consultation for patients with fever or respiratory symptoms. Here, we present the overall concept, advantages, and limitations of the COVID-19 WT screening center. The WT center increases patient access to the screening clinics and adequately protects healthcare personnel while reducing the consumption of personal protective equipment. It can also increase the number of people tested by 9–10 fold. However, there is a risk of cross-infection at each stage of screening treatment, including the booths, and adverse reactions with disinfection of the booths. These limitations can be overcome using mobile technology and increasing the number of booths to reduce congestion inside the center, reducing booth volume for sufficient and rapid ventilation, and using an effective, harmless, and certified environmental disinfectant. A WT center can be implemented in other institutions and countries and modified depending on local needs to cope with the COVID-19 pandemic.

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<![CDATA[Use of Convalescent Plasma Therapy in Two COVID-19 Patients with Acute Respiratory Distress Syndrome in Korea]]> https://www.researchpad.co/article/Nb2f341c1-1a6c-4a43-a406-469ba454fc16

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus-2 not yet has established its treatment, but convalescent plasma has been expected to increase survival rates as in the case with other emerging viral infections. We describe two cases of COVID-19 treated with convalescent plasma infusion. Both patients presented severe pneumonia with acute respiratory distress syndrome and showed a favorable outcome after the use of convalescent plasma in addition to systemic corticosteroid. To our knowledge, this is the first report of the use of convalescent plasma therapy for COVID-19 in Korea.

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<![CDATA[Clinical Course and Outcomes of Patients with Severe Acute Respiratory Syndrome Coronavirus 2 Infection: a Preliminary Report of the First 28 Patients from the Korean Cohort Study on COVID-19]]> https://www.researchpad.co/article/Nba639086-6c88-41c9-9260-f3f9aee1bf37

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pneumonia emerged in Wuhan, China in December 2019. In this retrospective multicenter study, we investigated the clinical course and outcomes of novel coronavirus disease 2019 (COVID-19) from early cases in Republic of Korea.

Methods

All of the cases confirmed by real time polymerase chain reaction were enrolled from the 1st to the 28th patient nationwide. Clinical data were collected and analyzed for changes in clinical severity including laboratory, radiological, and virologic dynamics during the progression of illness.

Results

The median age was 40 years (range, 20–73 years) and 15 (53.6%) patients were male. The most common symptoms were cough (28.6%) and sore throat (28.6%), followed by fever (25.0%). Diarrhea was not common (10.7%). Two patients had no symptoms. Initial chest X-ray (CXR) showed infiltration in 46.4% of the patients, but computed tomography scan confirmed pneumonia in 88.9% (16/18) of the patients. Six patients (21.4%) required supplemental oxygen therapy, but no one needed mechanical ventilation. Lymphopenia was more common in severe cases. Higher level of C-reactive protein and worsening of chest radiographic score was observed during the 5–7 day period after symptom onset. Viral shedding was high from day 1 of illness, especially from the upper respiratory tract (URT).

Conclusion

The prodromal symptoms of COVID-19 were mild and most patients did not have limitations of daily activity. Viral shedding from URT was high from the prodromal phase. Radiological pneumonia was common from the early days of illness, but it was frequently not evident in simple CXR. These findings could be plausible explanations for the easy and rapid spread of SARS-CoV-2 in the community.

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<![CDATA[School Opening Delay Effect on Transmission Dynamics of Coronavirus Disease 2019 in Korea: Based on Mathematical Modeling and Simulation Study]]> https://www.researchpad.co/article/N87673cd9-2cd9-40fe-9769-0887353b9cbc

Background

Nonpharmaceutical intervention strategy is significantly important to mitigate the coronavirus disease 2019 (COVID-19) spread. One of the interventions implemented by the government is a school closure. The Ministry of Education decided to postpone the school opening from March 2 to April 6 to minimize epidemic size. We aimed to quantify the school closure effect on the COVID-19 epidemic.

Methods

The potential effects of school opening were measured using a mathematical model considering two age groups: children (aged 19 years and younger) and adults (aged over 19). Based on susceptible-exposed-infectious-recovered model, isolation and behavior-changed susceptible individuals are additionally considered. The transmission parameters were estimated from the laboratory confirmed data reported by the Korea Centers for Disease Control and Prevention from February 16 to March 22. The model was extended with estimated parameters and estimated the expected number of confirmed cases as the transmission rate increased after school opening.

Results

Assuming the transmission rate between children group would be increasing 10 fold after the schools open, approximately additional 60 cases are expected to occur from March 2 to March 9, and approximately additional 100 children cases are expected from March 9 to March 23. After March 23, the number of expected cases for children is 28.4 for 7 days and 33.6 for 14 days.

Conclusion

The simulation results show that the government could reduce at least 200 cases, with two announcements by the Ministry of education. After March 23, although the possibility of massive transmission in the children's age group is lower, group transmission is possible to occur.

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<![CDATA[Out-of-Hospital Cohort Treatment of Coronavirus Disease 2019 Patients with Mild Symptoms in Korea: an Experience from a Single Community Treatment Center]]> https://www.researchpad.co/article/N640c0acb-b1ac-4dda-a166-ef9bd0885c67

The outbreak of Coronavirus Disease 2019 (COVID-19) caused a worldwide pandemic. Less than 6 weeks after the first confirmed cases in Korea, the patient number exceeded 5,000, which overcrowded limited hospital resources and forced confirmed patients to stay at home. To allocate medical resources efficiently, Korea implemented a novel institution for the purpose of treating patients with cohort isolation out of hospital, namely the Community Treatment Center (CTC). Herein, we report results of the initial management of patients at one of the largest CTC in Korea. A total of 309 patients were admitted to our CTC. During the first two weeks, 7 patients were transferred to the hospital because of symptom aggravation and 107 patients were discharged without any complication. Although it is a novel concept and may have some limitations, CTC may be a very cost-effective and resource-saving strategy in managing massive cases of COVID-19 or other emerging infectious diseases.

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<![CDATA[A Lesson from Temporary Closing of a Single University-affiliated Hospital owing to In-Hospital Transmission of Coronavirus Disease 2019]]> https://www.researchpad.co/article/N4b528dcc-2ff1-4a87-abce-8dbecfbf0f47 ]]> <![CDATA[A Nationwide Survey on the Hospital Vaccination Policies in Korea]]> https://www.researchpad.co/article/N0d33187d-7d88-4b55-8242-6e5d2f3946d6

Background

Healthcare personnel (HCP) are at risk of being exposed to or transmitting infections in hospitals, and vaccination against vaccine-preventable diseases (VPDs) is a well-known preventive strategy. Vaccination against influenza, hepatitis B virus, measles-mumps-rubella, varicella, and pertussis is recommended for HCP. However, there is no information on the current status of hospitals' vaccination policies for HCP in Korea.

Methods

We conducted a nationwide survey on hospital vaccination policies and barriers to implementing recommended vaccination programs in 2018. The online survey questionnaire was distributed to 652 hospitals, and 200 of them responded.

Results

Of the 200 surveyed hospitals, 151 (75.5%) conducted a pre-employment screening program for at least one VPD, and 196 (98%) had vaccination programs that included at least one vaccine. Influenza vaccine was most commonly included in their programs (97.5%, n = 195), followed by hepatitis B vaccines (69%, n = 138). However, < 25% of the hospitals included other vaccines in their policies (measles-mumps-rubella, 24.5%; varicella, 18.5%; pertussis, 11%). Only 13 hospitals (6.5%) included the five recommended vaccines for HCP in their policies. Influenza vaccination coverage had a mean of 89.9% and was significantly higher in hospitals fully funding the vaccination cost (91.8% vs. 80.4%, P < 0.001). Among hospitals funding influenza vaccines, the coverage was lower in hospitals with ≥ 700 beds (−6.5%, P = 0.003). Hospitals' financial burden was the most important barrier to implementing vaccination polices as recommended (78.6%, 121/154), followed by lack of awareness (21%) or campaign (21%) and lack of leadership (17%).

Conclusion

Despite the recommendations on vaccination for HCP, the vaccination policies for HCP differ in hospitals and appear to be insufficient to protect HCP and prevent nosocomial transmission. Strong leadership of each hospital to protect HCP and financial support from the government are required to implement appropriate vaccination policies in hospitals.

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<![CDATA[Analysis on 54 Mortality Cases of Coronavirus Disease 2019 in the Republic of Korea from January 19 to March 10, 2020]]> https://www.researchpad.co/article/N09b8d391-4979-483a-b0fa-8b28e7ae307c

Since the identification of the first case of coronavirus disease 2019 (COVID-19), the global number of confirmed cases as of March 15, 2020, is 156,400, with total death in 5,833 (3.7%) worldwide. Here, we summarize the morality data from February 19 when the first mortality occurred to 0 am, March 10, 2020, in Korea with comparison to other countries. The overall case fatality rate of COVID-19 in Korea was 0.7% as of 0 am, March 10, 2020.

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<![CDATA[Understanding and Interpretation of Case Fatality Rate of Coronavirus Disease 2019]]> https://www.researchpad.co/article/Na6f086f8-61cd-4758-9a92-755172f63fc4 ]]>