Last data update: May 06, 2024. (Total: 46732 publications since 2009)
Records 1-4 (of 4 Records) |
Query Trace: Xayavong MV[original query] |
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Experimental transfusion-induced Babesia microti infection: dynamics of parasitemia and immune responses in a rhesus macaque model
Gumber S , Nascimento FS , Rogers KA , Bishop HS , Rivera HN , Xayavong MV , Devare SG , Schochetman G , Amancha PK , Qvarnstrom Y , Wilkins PP , Villinger F . Transfusion 2016 56 1508-19 BACKGROUND: Babesiosis is an emerging tick-borne infection in humans. The increasing numbers of reported cases of transfusion-associated babesiosis (TAB), primarily caused by Babesia microti, represents a concern for the safety of the US blood supply. STUDY DESIGN AND METHODS: This study investigated kinetics of parasitemia and innate immune responses and dynamics of antibody responses during B. microti infection in rhesus macaques (RMs) using blood smears, quantitative polymerase chain reaction (qPCR), flow cytometry, and indirect fluorescent antibody testing. A total of six monkeys were transfused with either hamster or monkey-passaged B. microti-infected red blood cells (two and four monkeys, respectively) simulating TAB. RESULTS: The prepatent period in monkeys inoculated with hamster-passaged B. microti was 35 days compared with 4 days in monkeys transfused with monkey-passaged B. microti; the latter monkeys also had markedly higher parasitemia levels. The duration of the window period from the first detected parasitemia by qPCR analysis to the first detected antibody response ranged from 10 to 17 days. Antibody responses fluctuated during the course of the infection. Innate responses assessed by the frequencies of monocytes and activated B cells correlated with the kinetics and magnitude of parasitemia. On Day 14, additional activation peaks were noted for CD14+CD16+ and CD14-CD16+ monocytes and for CD11c+ myeloid dendritic cells, but only in animals transfused with monkey-passaged B. microti. Parasitemia persisted in these immunocompetent animals, similar to human infection. CONCLUSION: The results suggest that transfusion-associated transmission of B. microti leads to rapid onset of parasitemia (Day 4) in RMs, detectable antibody response 14 days later, and persistent parasitemia. |
Spread of the rat lungworm (Angiostrongylus cantonensis) in giant African land snails (Lissachatina fulica) in Florida, USA
Iwanowicz DD , Sanders LR , Schill WB , Xayavong MV , da Silva AJ , Qvarnstrom Y , Smith T . J Wildl Dis 2015 51 (3) 749-53 The rat lungworm (Angiostrongylus cantonensis) is a parasitic nematode that causes rat lungworm disease. It is the leading cause of eosinophilic meningitis and is a zoonotic health risk. We confirmed the presence of A. cantonensis using species-specific, quantitative PCR in 18 of 50 (36%) giant African land snails (Lissachatina fulica) collected from Miami, Florida, US in May 2013. These snails were collected from seven of 21 core areas that the Florida Department of Agriculture and Consumer Services monitor weekly. Rat lungworms have not previously been identified in these areas. Duplicate DNA extractions of foot muscle tissue from each snail were tested. Of the seven core areas we examined, six were positive for A. cantonensis and prevalence of infection ranged from 27% to 100%. Of the 18 positive snails, only five were positive in both extractions. Our results confirm an increase in the range and prevalence of rat lungworm infection in Miami. We also emphasize the importance of extracting sufficient host tissue to minimize false negatives. |
First report of human babesiosis in Australia
Senanayake SN , Paparini A , Latimer M , Andriolo K , Dasilva AJ , Wilson H , Xayavong MV , Collignon PJ , Jeans P , Irwin PJ . Med J Aust 2012 196 (5) 350-2 We report the first human case of babesiosis in Australia, thought to be locally acquired. |
The third described case of transfusion-transmitted Babesia duncani
Bloch EM , Herwaldt BL , Leiby DA , Shaieb A , Herron RM , Chervenak M , Reed W , Hunter R , Ryals R , Hagar W , Xayavong MV , Slemenda SB , Pieniazek NJ , Wilkins PP , Kjemtrup AM . Transfusion 2011 52 (7) 1517-22 BACKGROUND: Almost all of the reported US tick-borne and transfusion-associated Babesia cases have been caused by Babesia microti, which is endemic in the Northeast and upper Midwest. We investigated a case caused by B. duncani (formerly, the WA1-type parasite), in a 59-year-old California resident with sickle cell disease (HbSS) whose only risk factor for infection was receipt of red blood cell transfusions. CASE REPORT: The patient's case was diagnosed in September 2008: intraerythrocytic parasites were noted on a blood smear, after a several-month history of increasing transfusion requirements. Molecular and indirect fluorescent antibody (IFA) analyses were negative for B. microti but were positive for B. duncani (IFA titer, 1:1024). The complete 18S ribosomal RNA gene of the parasite was amplified from a blood specimen; the DNA sequence was identical to the sequence for the index WA1 parasite isolated in 1991. The patient's case prompted a transfusion investigation: 34 of 38 pertinent blood donors were evaluated, none of whom tested positive by B. microti IFA. The implicated donor-a 67-year-old California resident-had a B. duncani titer of 1:4096; B. duncani also was isolated by inoculating jirds (Mongolian gerbils) with a blood specimen from March 2009, more than 10 months after his index donation in April 2008. The patient's case was diagnosed more than 4 months after the implicated transfusion in May 2008. CONCLUSIONS: This patient had the third documented transfusion case caused by B. duncani. His case underscores the fact that babesiosis can be caused by agents not detected by molecular or serologic analyses for B. microti. |
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