• Parasites, Hosts and Diseases
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• v.36 no.3
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• pp.203-206
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• 1998

Two-day-old commercial chicks were inoculated orally with 2 × 106 oocysts of Cwptosporinium bailevi and vaccinated with 103.5 EID50/head of a commercially available avian infectious bronchitis (IB) live virus vaccine at 4 and 14 days following inoculation. Chicks infected with C. baileyi were shown to have an immunosuppressive effect on IB virus. It is concluded that infection with the protozoon in early life may increase their susceptibility to IB.

• Parasites, Hosts and Diseases
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• v.49 no.3
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• pp.221-228
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• 2011

Rodent malaria parasites, such as Plasmodium berghei, are practical and useful model organisms for human malaria research because of their analogies to the human malaria in terms of structure, physiology, and life cycle. Exploiting the available genetic sequence information, we constructed a cDNA library from the erythrocytic stages of P. berghei and analyzed the expressed sequence tag (EST). A total of 10,040 ESTs were generated and assembled into 2,462 clusters. These EST clusters were compared against public protein databases and 48 putative new transcripts, most of which were hypothetical proteins with unknown function, were identified. Genes encoding ribosomal or membrane proteins and purine nucleotide phosphorylases were highly abundant clusters in P. berghei. Protein domain analyses and the Gene Ontology functional categorization revealed translation/protein folding, metabolism, protein degradation, and multiple family of variant antigens to be mainly prevalent. The presently-collected ESTs and its bioinformatic analysis will be useful resources to identify for drug target and vaccine candidates and validate gene predictions of P. berghei.

• Parasites, Hosts and Diseases
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• v.53 no.2
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• pp.177-187
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• 2015

Merozoite surface proteins (MSPs) of malaria parasites play critical roles during the erythrocyte invasion and so are potential candidates for malaria vaccine development. However, because MSPs are often under strong immune selection, they can exhibit extensive genetic diversity. The gene encoding the merozoite surface protein-3 (MSP-3) of Plasmodium falciparum displays 2 allelic types, K1 and 3D7. In Thailand, the allelic frequency of the P. falciparum msp-3 gene was evaluated in a single P. falciparum population in Tak at the Thailand and Myanmar border. However, no study has yet looked at the extent of genetic diversity of the msp-3 gene in P. falciparum populations in other localities. Here, we genotyped the msp-3 alleles of 63 P. falciparum samples collected from 5 geographical populations along the borders of Thailand with 3 neighboring countries (Myanmar, Laos, and Cambodia). Our study indicated that the K1 and 3D7 alleles co-existed, but at different proportions in different Thai P. falciparum populations. K1 was more prevalent in populations at the Thailand-Myanmar and Thailand-Cambodia borders, whilst 3D7 was more prevalent at the Thailand-Laos border. Global analysis of the msp-3 allele frequencies revealed that proportions of K1 and 3D7 alleles of msp-3 also varied in different continents, suggesting the divergence of malaria parasite populations. In conclusion, the variation in the msp-3 allelic patterns of P. falciparum in Thailand provides fundamental knowledge for inferring the P. falciparum population structure and for the best design of msp-3 based malaria vaccines.

• Parasites, Hosts and Diseases
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• v.46 no.3
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• pp.195-198
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• 2008

Plasmodium falciparum liver stage antigen-1 (PfLSA-1) is one of the few antigens expressed exclusively in liver stage parasites. In this study, we evaluated the antibody responses against recombinant PfLSA-1 in naturally infected individuals in Myanmar. High levels of antibody responses (70.7%) were detected in 82 serum samples from 116 infected individuals, and IgG responses to PfLSA-1 principally composed of responses of IgG1 and IgG3 subclasses. These results show that PfLSA-1 elicits effective antibody responses in individuals infected with P. falciparum, and thus it could be not only an attractive candidate protein for vaccine development, but also a useful antigen for serodiagnosis of the infection.

• Parasites, Hosts and Diseases
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• v.58 no.2
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• pp.173-179
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• 2020

Leishmaniasis is a prevalent cause of death and animal morbidity in underdeveloped countries of endemic area. However, there is few vaccine and effective drugs. Antimicrobial peptides are involved in the innate immune response in many organisms and are being developed as novel drugs against parasitic infections. In the present study, we synthesized a 5-amino acid peptide REDLK, which mutated the C-terminus of Pseudomonas exotoxin, to identify its effect on the Leishmania tarentolae. Promastigotes were incubated with different concentration of REDLK peptide, and the viability of parasite was assessed using MTT and Trypan blue dye. Morphologic damage of Leishmania was analyzed by light and electron microscopy. Cellular apoptosis was observed using the annexin V-FITC/PI apoptosis detection kit, mitochondrial membrane potential assay kit and flow cytometry. Our results showed that Leishmania tarentolae was susceptible to REDLK in a dose-dependent manner, disrupt the surface membrane integrity and caused parasite apoptosis. In our study, we demonstrated the leishmanicidal activity of an antimicrobial peptide REDLK from Pseudomonas aeruginosa against Leishmania tarentolae in vitro and present a foundation for further research of anti-leishmanial drugs.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.100-103
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• 2002

Streptococcus milleri Goup Bacteria(SMG) comprise three species, Streptococcus anginosus, Streptococcus intermedius, Streptococcus constellatus. Although they are commensal organism, they can be pathogenic. SMG can be aggressive pathogen in the head and neck with a propensity for abscess formation and local extension of the infection. SMG is culturally and biochemically variable, which makes it hard for the clinicians to recognize it. Hence, it seems that this organism has been relatively neglected. Most of the Lancefield F streptococci are SMG. We report one patient who had Group F streptococcal bacteremia and subdural abscess. According to his medical history, he was diagnosed as membranoproliperative glomerulonephritis three years ago. He complained headache although he was treated by appropiate antibiotics. Brain CT was used as a tool to identify the brain abscess. He had surgical drainage and was treated with IV antibiotics postoperatively.

• Pediatric Infection and Vaccine
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• v.9 no.1
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• pp.110-116
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• 2002

Tuberculous otitis media is a very rare disease in extrapulmonary tuberculosis and in chronic otitis media nowadays. The characteristic signs seem to have altered from the past ones. And the suspicion index is very low that there is often a considerable delay prior to diagnosis. This might result in irreversible complications such as hearing loss, facial nerve paralysis and labyrinthitis. It is difficult to be defined by culture, so many patients with tuberculous otitis media are subjected to have surgery without a correct etiologic diagnosis. Therefore bacteriologic study of secretion and pathologic examinations of biopsied tissue are mandatory. We report one year and 11 months old boy with tuberculous otitis media having painful otorrhea and perforated tympanic membrane diagnosed by histologic finding and polymerase chain reaction(PCR). And we would like to emphasize the fact that tuberculous otitis media must be considered in the differential diagnosis of persistent suppurative otitis media despite appropriate antibiotic therapy considering the increasing tendency in incidence of Tuberculosis in Korea these days.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.308-313
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• 1997

Ceftriaxone, an effective third generation cephalosporin with a wide range of antimicrobial activity, has become widely used by pediatricians for a variety of bacterial infections including meningitis. It has been associated with the development of sludge or stone in the gallbladder of some patients treated with this drug. Ceftriaxone associated biliary sludge has unusual acoustic characteristics and resembles gallstone. The sludge can cause symptoms such as cramping abdominal pain, and disappears after stopping ceftriaxone administration. Because of these seemingly confusing observations, it is important for the clinicians to recognize these findings that ceftriaxone treatment can cause. We report a case of ceftriaxone associated biliary sludge in Korean children. A 6-year-old girl who was treated for meningitis with ceftriaxone (100mg/kg/day) developed cramping upper abdominal pain from 5th hospital day. Physical examination, liver function tests and X-ray revealed no specific abnormal findings. But abdominal ultrasound revealed high amplitude echogenic sludge with prominent post-acoustic shadow in gallbladder and its diameter was 1.5cm. We stopped ceftriaxone administration and tried conservative care. Abdominal cramping pain subsided after 3 days of ceftriaxone removal. Second abdominal ultrasound confirmed the disappearance of sludge at 3 weeks later.

• Pediatric Infection and Vaccine
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• v.4 no.2
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• pp.293-297
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• 1997

Malaria, caused by any of four species of protozoan parasites of the genus Plasmodium, is charaterized by high fever, anemia and splenomegaly. Although malaria is a cause of significant morbidity and mortality worldwide, in Korea indigenous malaria has been believed to be eradicated by 1984. However, since the case report of native malaria in 1993, reported cases have been increased annually, reaching more than 300 cases in 1996. We experienced a 2 years-old male with fever, severe anemia and splenomegaly who resided in Inchon city. He had the history of travelling to the area (Yunchon) near western Demilitarized Zone for 1 month this summer. After more than 2 weeks without special attention, he was presented with pallor, anemia and splenomegaly. He was diagnosed to have malaria by Plasmodium vivax with the help of peripheral blood smears which showed various forms of malaria, i.e., ring form, trophozoites, shizonts and gametocytes. He was treated successfully with hydroxychloroquine and primaquine. We report this case with brief review of related literature.

• Pediatric Infection and Vaccine
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• v.25 no.1
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• pp.45-49
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• 2018

Group B streptococcus (GBS) is the leading cause of neonatal morbidity and mortality. Late-onset GBS disease commonly manifests as occult bacteremia or meningitis. Approximately 50% of survivors of late-onset meningitis have long-term neurologic sequelae. Cerebrovascular complications are often associated with unfavorable clinical outcomes of GBS meningitis. There have been a few reports of cerebral infarction accompanied by GBS meningitis. We report a 29-day-old girl with severe, widespread cerebral infarction due to late-onset GBS meningitis. Isolated GBS strain from this patient was serotype III, ST-19. Currently, she has cortical blindness and significant developmental delay.