Asian Genotype Research Articles

Difference between the abilities of human Fcgamma receptor-expressing CV-1 cells to neutralize American and Asian genotypes of dengue virus 2.

Sera from patients involved in a Peruvian outbreak of dengue virus serotype 1 infection cross-neutralized the American genotype of dengue virus serotype 2 up to 100-fold more efficiently than they did the virulent Asian genotype of dengue virus serotype 2, as determined by a plaque reduction neutralization test (PRNT) with CV-1 fibroblasts modified to express human Fcgamma receptor CD32. The concordant preferential immune enhancement of the Asian genotype of dengue virus serotype 2 in human monocytes suggests that such a modification might strengthen the correlation between the PRNT titer and protection.

Chikungunya virus is a cause of encephalitis in children in bellary, India

Introduction: Chikungunya virus, a single stranded RNA Alphavirus of the family Togaviridae, is transmitted to humans by the bite of Aedes aegypti, Aedes albopictus and other mosquitoes. An epidemic starting in Reunion Islands in March 2005 spread to Southern India, affecting 1.3 million people between Oct 2005 and Oct 2006. The epidemic reached Bellary, Karnataka in southern India by Dec 2005. Methods: From Oct 2005 to Dec 2007, children admitted to the paediatric department of the Vijayanagar Institute of Medical Sciences with an acute encephalitis syndrome were prospectively studied. All children presenting to the paediatric ward were recruited if they had suspected CNS infection or acute flaccid paralysis [and] fever or history of fever in the previous 2 weeks, together with one or more of the following: meningism (neck stiffness), photophobia, severe headache meriting lumbar puncture, altered mental state, reduced consciousness, convulsions, focal neurological signs or acute flaccid paralysis. Results: 243 patients have been recruited to date. Between April and Oct 2006, 8 children had positive plasma PCR tests for Chikungunya RNA and are described in more detail. Viral RNA was also detected by PCR in the CSF of 3 of these 8. Mean age was 6 years, range 8 months to 11 years, 5 were girls. 3 children had a rash at some stage in their illness and one had conjunctivitis. Altered mental state was reported in 7, and 6 had a GCS of less than 15 at admission. One had deafness, 3 had nausea and vomiting, and 3 had meningism. 7 had seizures, amongst whom 4 had an episode of status epilepticus (seizure lasting more than 30 minutes). 3 were aphasic during their illness and 4 had extensor plantar reflexes. There were no fatalities. At discharge, 2 patients had ongoing aphasia. The remaining 4 with a reduced GCS at admission had recovered to full coma score. Sequencing information obtained from the E1 envelope gene from plasma and CSF samples confirmed that the chikungunya genomes are of the East African lineage, which appears to have caused the more severe epidemic form of illness, compared to the Asian genotype which previously circulated in India. Conclusions: Chikungunya virus causes encephalitis in children and may be found in the CSF. It can cause severe neurological disease sequelae although the extent to which these sequelae will persist is uncertain. Given frequent travel between Asia and Europe and the potential for autochtonous transmission, as has occurred in Italy, we need to be increasingly aware of global disease outbreaks. A CASE OF HYPERCALCAEMIA IN THE RETURNING

Two Imported Chikungunya Cases, Taiwan

Two Imported Chikungunya Cases, Taiwan

Genetic relationships among West African okra (Abelmoschus caillei) and Asian genotypes (Abelmoschus esculentus) using RAPD

Ninety-three accessions of okra which comprises of 50 West African genotypes (Abelmoschus caillei) and 43 Asian genotypes (A. esculentus) were assessed for genetic distinctiveness and relationships using random amplified polymorphic DNA (RAPD). The molecular analysis showed that all the thirteen primers used revealed clear distinction between the two genotypes. There were more diversity among the Asian genotypes; this might be due to the fact that they were originally collected from six different countries in the region. Six duplicates accessions were discovered while accession TOT7444 distinguished itself from the other two okra species, an indication which suggests that it might belong to a different species.

Phylogeny of dengue viruses circulating in Jeddah, Saudi Arabia: 1994 to 2006

The nucleotide sequence of the 240 bp E/NS1 junction of 81 dengue viruses isolated from cases in Jeddah, Saudi Arabia was determined and used to serotype the viruses. The nucleotide sequences of the complete Envelope (E) genes of 19 isolates were used for a phylogenetic analysis of the dengue viruses circulating in Saudi Arabia from 1994 to 2006. Three of the four dengue serotypes (DENV-1, DENV-2 and DENV-3) were found to circulate, often with more than one serotype in each outbreak. There was a major outbreak caused by DENV-1 and DENV-2 in 1994 while DENV-3 emerged in 1997. In the summer of 2004, all three serotypes were isolated and this gave way to an extended outbreak of DENV-1 that stretched from the summer of 2005 through early 2006. In the 1994 outbreak, the DENV-1 circulating was from the America-Africa genotype (lineage India-2) while the most recent outbreak in 2005 and 2006 was caused by a different DENV-1 strain from genotype Asia (lineage Asia-2), suggesting a re-introduction of DENV-1 a decade after the first introduction in 1994. There has been no change in the genotypes of DENV-2 (cosmopolitan genotype) and DENV-3 (genotype III) circulating since introduction in 1994 and 1997, respectively.

Improvement of DNA Extraction Method for Dried Blood Spots and Comparison of Four PCR Methods for Detection of Babesia gibsoni (Asian Genotype) Infection in Canine Blood Samples

To eradicate canine babesiosis in epidemic areas, mass-screening of the infection situation of Babesia gibsoni including occult infection is necessary. The development of cost-effective method for storage and transport of blood samples is required. A highly efficient DNA extraction procedure from dried blood spots (DBS) onto Whatman 3MM filter paper was developed for the diagnosis of B. gibsoni infection in dog by PCR. In 3 extraction methods, Chelex-based method in combination with saponin washing and phenol-chloroform-isoamyl alcohol extraction (Saponin-PCI method) provided the best results. Sensitivity of the 4 previously described PCR methods for detection of B. gibsoni infection was also compared using serially diluted blood samples of B. gibsoni-infected dogs. The PCR method using Gib599F/Gib1270R primer pair provided the best performance. To evaluate the stability of DNA in DBS, DBS of B. gibsoni-infected dogs stored at room temperature for 2 months. The stability was superior to whole blood samples stored at -20 degrees C for 2 months. This highly efficient DNA extraction method on DBS using Whatman 3MM filter paper has potential to be cost-effective and high performance tool for storage, and molecular diagnosis of clinical blood sample from dog. This procedure in combination with the PCR method using Gib599F/Gib1270R primer pair may greatly assist in diagnosis of B. gibsoni infection in dog populations that are geographically distant.

Primary and Secondary Infections ofMacaca fascicularisMonkeys with Asian and American Genotypes of Dengue Virus 2

The goal of this study was to compare the immune response and the protection capacity induced by the dengue virus 2 (DENV-2) American and Asian genotypes in Macaca fascicularis monkeys. Animals were infected with American or Asian DENV-2 strains and challenged 1 year later with a DENV-2 Asian genotype strain. The viremia and monkey antibody levels were similar for the different strains after primary and secondary infection; however, the functionality of the antibody response was different. A limited viral replication was demonstrated after the secondary infection in all the monkeys. No virus was isolated in tissue culture, while reverse transcription-PCR showed a late positive reaction in four of five challenged monkeys. The immunoglobulin M response pattern and the detection of antibodies to specific proteins by Western blotting supported the protection data. Despite the demonstration of the protective effect after homologous challenge, a strong anamnestic antibody response was observed.

Sequence conservation in the rRNA first internal transcribed spacer region of Babesia gibsoni genotype Asia isolates

Babesia gibsoni genotype Asia is a small, tick-transmitted intraerythrocytic protozoan that parasitizes dogs. Reports suggest that it is increasingly diagnosed in the United States. The clinical outcome of infection with this piroplasm is often variable, leading us to hypothesize that the different clinical outcomes resulting from B. gibsoni genotype Asia infection are due to genetically distinguishable strains that differ in virulence. As a first step to assess the genetic variability of B. gibsoni isolates originating from the southeastern United States, we sequenced the rRNA first internal transcribed spacer region of recent isolates from Georgia and Alabama, and compared these sequences with isolates originating from Japan and Australia. All isolates examined proved to be genetically identical at the first internal transcribed spacer region, although this region differed distinctly from other Babesia species and closely related apicomplexan species. Although negating our hypothesis, this information gives us insight into the recent evolutionary history and spread of B. gibsoni genotype Asia in dogs in the U.S. Our research suggests that the gradual rise in prevalence of canine babesiosis due to B. gibsoni genotype Asia in the United States may be a result of clonal expansion of a single strain within a susceptible host population.

East Central South African Genotype as the Causative Agent in Reemergence of Chikungunya Outbreak in India

Chikungunya fever is an important arboviral infection prevalent through out Africa and Southeast Asia. Recently, in 2006, it has reemerged in many parts of India, affecting more than a million persons. A detail serological, virological, and molecular investigation of this unprecedented outbreak was carried out by collecting and studying 540 samples from all the affected regions of India during this epidemic. An in-depth investigation revealed the presence of anti-Chikungunya antibodies in 68% of the samples and genomic RNA in 49% of them. In addition 32 Chikungunya viruses were isolated from 45 representative polymerase chain reaction-positive samples. The nucleotide sequences of partial E1 gene of 25 representative Chikungunya viruses were deciphered. The sequence analysis indicated that all the isolates of this epidemic belonged to the new Indian Ocean island clade of East Central South (ECS) African genotype. Phylogenetic analysis also revealed that earlier Indian isolates were clustered into the Asian genotype. This study conclusively proved the genotype shift from Asian to ECS African as the major factor in the reemergence of Chikungunya in an unprecedented outbreak in India after a gap of 32 years.

Successful allogeneic stem cells transplantation in severe aplastic anaemia complicated by dengue Fever.

Aplastic anaemia is characterized by severe compromise of haematopoiesis and hypocellular bone marrow. Haemorrhagic episodes in patients with aplastic anemia occur usually secondary to thrombocytopenia and require frequent support with platelet concentrates and other blood products. Infection with dengue virus (particularly dengue sero type-2 of South Asian genotype) is associated with dengue haemorrhagic fever. Dengue infection further worsens the disease process in patients with aplastic anaemia due to uncontrolled haemorrhagic diathesis and major organ failure, which may prove fatal in these already immunocompromised patients, if not treated in time. Recent epidemics of dengue haemorrhagic fever has not only affected the southern region of our country but also spread to other areas of the country. With this background, we report a case of aplastic anaemia complicated by dengue haemorrhagic fever who achieved successful engraftment after allogeneic stem cell transplantation from sibling brother and is having normal healthy post transplant life.

Genetic divergence of Chikungunya viruses in India (1963–2006) with special reference to the 2005–2006 explosive epidemic

Re-emergence of Chikungunya (CHIK), caused by CHIK virus, was recorded in India during 2005-2006 after a gap of 32 years, causing 1.3 million cases in 13 states. Several islands of the Indian Ocean reported similar outbreaks in the same period. These outbreaks were attributed to the African genotype of CHIK virus. To examine relatedness of the Indian isolates (IND-06) with Reunion Island isolates (RU), full-genome sequences of five CHIK virus isolates representative of different Indian states were determined. In addition, an isolate obtained from mosquitoes in the year 2000 (Yawat-2000), identified as being of the African genotype, and two older strains isolated in 1963 and 1973 (of the Asian genotype), were sequenced. The IND-06 isolates shared 99.9 % nucleotide identity with RU isolates, confirming involvement of the same strain in these outbreaks. The IND-06 isolates shared 98.2 % identity with the Yawat-2000 isolate. Of two crucial substitutions reported for RU isolates in the E1 region, M269V was noted in the Yawat-2000 and IND-06 isolates, whereas D284E was seen only in the IND-06 isolates. The A226V shift observed with the progression of the epidemic in Reunion Island, probably associated with adaptation to the mosquito vector, was absent in all of the Indian isolates. Three unique substitutions were noted in the IND-06 isolates: two (T128K and T376M) in the Nsp1 region and one (P23S) in the capsid protein. The two Asian strains showed 99.4 % nucleotide identity to each other, indicating relative stability of the virus. No evidence of recombination of the Asian and African genotypes, or of positive selection was observed. The results may help in understanding the association, if any, of the unique mutations with the explosive nature of the CHIK outbreak.

First Evidence ofBabesia gibsoni(Asian genotype) in Dogs in Western Europe

Canine babesiosis in Europe is generally caused by Babesia canis canis and Babesia canis rossi. Here we describe the first two autochthonous cases of Babesia gibsoni (Asian genotype) infection in Germany. Two American pit bull terriers showed clinical and hematologic signs consistent with babesiosis. Polymerase chain reaction (PCR) analysis of the 18S rDNA of blood samples revealed 486 bp fragments. The sequences were 100% identical to each other and 100% identical to Babesia gibsoni (Asian genotype). These results represent the first genetic evidence of Babesia gibsoni (Asian genotype) parasites in dogs in Western Europe.

Neurocysticercosis as Solitary Parenchymal Lesion Confirmed by Mitochondrial Deoxyribonucleic Acid Sequence Analysis-Case Report-

A 38-year-old Japanese woman presented with neurocysticercosis manifesting as mild hemiparesis. Magnetic resonance (MR) imaging with gadolinium showed a solitary parenchymal lesion. MR spectroscopy of the mass showed a relatively low N-acetylaspartate peak. Enzyme-linked immunosorbent assay of the patient's cerebrospinal fluid using antibodies against several parasite antigens was negative. Surgical resection of the lesion was performed. The histological findings showed the possibility of parasitic infection such as neurocysticercosis, although the definitive type of parasite was not confirmed. Sequencing of cytochrome c oxidase subunit 1 gene of mitochondrial deoxyribonucleic acid indicated the Asian genotype of Taenia solium. We propose that these new diagnostic techniques should be used more widely, especially for solitary lesions of neurocysticercosis.

ITS barcodes forTrichophyton tonsuransandT. equinum

Early molecular biosystematic studies of dermatophytes created considerable confusion about the taxonomic status of the horse-associated Trichophyton equinum vis-à-vis the anthropophilic T. tonsurans. Though this matter has recently been clarified, routine identification of these species based on the commonly used ribosomal internal transcribed spacer (ITS) sequence has been impractical. This is because, in the available sequences attributed to the species in GenBank, a clear species-level distinction does not appear to exist. In the present study, resequencing the ITS regions of several anomalous isolates is shown to eliminate this problem, which was mainly based on read errors in older sequences. Newly generated sequences and recent GenBank additions are analysed to show that T. equinum appears to be uniform in ITS sequence worldwide, while T. tonsurans is also uniform, excepting a single-base change found in one otherwise typical strain. Analysis also reveals a distinct, as yet incompletely classified Asian genotype that may belong to one or the other of these species. Standard ITS 'barcode sequences' are proposed for T. tonsurans and T. equinum, and a taxonomic neotype is designated to anchor the latter species. T. equinum var. autotrophicum is further evidenced as very closely related to T. equinum var. equinum, and the anomaly of its plesiomorphous phenotype is discussed in a population genetics context.

Dengue in the Americas and Southeast Asia: do they differ?

The populations of Southeast Asia (SE Asia) and tropical America are similar, and all four dengue viruses of Asian origin are endemic in both regions. Yet, during comparable 5-year periods, SE Asia experienced 1.16 million cases of dengue hemorrhagic fever (DHF), principally in children, whereas in the Americas there were 2.8 million dengue fever (DF) cases, principally in adults, and only 65,000 DHF cases. This review aims to explain these regional differences. In SE Asia, World War II amplified Aedes aegypti populations and the spread of dengue viruses. In the Americas, efforts to eradicate A. aegypti in the 1940s and 1950s contained dengue epidemics mainly to the Caribbean Basin. Cuba escaped infections with the American genotype dengue-2 and an Asian dengue-3 endemic in the 1960s and 1970s. Successive infections with dengue-1 and an Asian genotype dengue-2 resulted in the 1981 DHF epidemic. When this dengue-2 virus was introduced in other Caribbean countries, it encountered populations highly immune to the American genotype dengue-2. During the 1980s and 1990s, rapidly expanding populations of A. aegypti in Brazil permitted successive epidemics of dengue-1, -2, and -3. These exposures, however, resulted mainly in DF, with surprisingly few cases of DHF. The absence of high rates of severe dengue disease in Brazil, as elsewhere in the Americas, may be partly explained by the widespread prevalence of human dengue resistance genes. Understanding the nature and distribution of these genes holds promise for containing severe dengue. Future research on dengue infections should emphasize population-based designs.

Evaluation of PurifiedTaenia soliumGlycoproteins and Recombinant Antigens in the Serologic Detection of Human and Swine Cysticercosis

Cysticercosis caused by infection with embryonated eggs of Taenia solium is an important cause of neurological disease worldwide. On the basis of mitochondrial DNA analysis, T. solium is divided into 2 (African/American and Asian) genotypes. Glycoproteins (GPs) in cyst fluid purified from the 2 genotypes of T. solium were characterized and compared with the recombinant chimeric T. solium-Ag1V1/Ag2 protein (Rec-Ag1V1/Ag2) as serodiagnostic antigens. Immunoblot analysis revealed that banding patterns of GPs differed between the 2 genotypes because of posttranslation modification, especially glycosylation. The comparison of native GPs with Rec-Ag1V1/Ag2 by enzyme-linked immunosorbent assay demonstrated that there was no statistical difference in sensitivity. In addition, the conservation of the genes encoding Ag1V1 and Ag2 in T. solium worldwide was verified. These results indicate that Rec-Ag1V1/Ag2 has great potential for usefulness in serodiagnosis as an alternative to native antigens.

AEDES AEGYPTI VECTORIAL CAPACITY IS DETERMINED BY THE INFECTING GENOTYPE OF DENGUE VIRUS

Dengue viruses causing severe, hemorrhagic disease have displaced less virulent strains in the Americas during the past three decades. The American (AM) genotype of dengue serotype 2 has been endemic in the Western Hemisphere and South Pacific, causing outbreaks of dengue fever (DF), but has not been linked to dengue hemorrhagic fever (DHF). The Southeast Asian (SEA) genotype of dengue was introduced into this hemisphere in 1981, has caused outbreaks with numerous cases of DHF, and has displaced the AM genotype in several countries. We investigated the effect of viral genotype on the potential for transmission by infecting Aedes aegypti mosquitoes collected in South Texas with six viruses, representing these two genotypes. Viral replication in the midgut was significantly higher in SEA-infected mosquitoes, and virus-specific proteins could be detected in salivary glands 7 days earlier in SEA- than AM-infected mosquitoes. This much earlier appearance of dengue virus in salivary glands resulted in an estimated 2- to 65-fold increase in the vectorial capacity of these mosquitoes for the viruses that can cause DHF. This may be one of the mechanisms through which more virulent flaviviruses spread and displace others globally.

Genetic diversity of indigenous tropical fast-growing rhizobia isolated from soybean nodules

This study characterized genetically 30 fast-growing rhizobial strains isolated from nodules of Asian and modern soybean genotypes that had been inoculated with soils from disparate regions of Brazil. Analyses by rep-PCR (ERIC and REP) and RAPD indicated a high level of genetic diversity among the strains. The RFLP-PCR and sequencing analysis of the 16S rRNA genes indicated that none of the strains was related to Sinorhizobium (Ensifer) fredii, whereas most were related to Rhizobium tropici (although they were unable to nodulate Phaseolus vulgaris) and to Rhizobium genomic species Q. One strain was related to Rhizobium sp. OR 191, while two others were closely related to Agrobacterium (Rhizobium) spp.; furthermore, symbiotic effectiveness with soybean was maintained in those strains. Five strains were related to Bradyrhizobium japonicum and B. elkanii, with four of them being similar to strains carried in Brazilian inoculants, therefore modifications in physiological properties, as a shorter doubling time might have resulted from adaptation to local conditions. Phospholipid fatty acid analysis (PFLA) was less precise in delineating taxonomic relationships. The strains fit into eight Nod-factor profiles that were related to rhizobial species, but not to N2-fixation capacity or competitiveness. The data obtained highlight the diversity and promiscuity of rhizobia in the tropics, being capable of nodulating exotic legumes and might reflect ecological strategies to survive in N-poor soils; in addition, the diversity could also represent an important source of efficient and competitive rhizobial strains for the tropics. Putative new rhizobial species were detected only in undisturbed soils. Three species (R. tropici, B. japonicum and B. elkanii) were found under the more sustainable management system known as no-till, while the only species isolated from soils under conventional till was R. tropici. Those results emphasize that from the moment that agriculture was introduced into undisturbed soils rhizobial diversity has changed, being drastically reduced when a less sustainable soil management system was adopted.

Chikungunya Outbreaks Caused by African Genotype, India

Chikungunya fever is reported in India after 32 years. Immunoglobulin M antibodies and virus isolation confirmed the cause. Phylogenic analysis based on partial sequences of NS4 and E1 genes showed that all earlier isolates (1963–1973) were Asian genotype, whereas the current and Yawat (2000) isolates were African genotype.

Babesia gibsoni genotype Asia in dogs from Brazil

Babesia gibsoni was first recognized in India in 1910. Analysis of 18S rRNA has shown that there are at least three distinct isolates that are morphologically identical. Although organisms similar to B. gibsoni have been identified in peripheral blood smears from one dog in Brazil, this isolate has not been molecularly characterized. Accordingly, we obtained blood samples from 16 dogs with intraerythrocytic inclusion bodies. DNA was extracted and amplified with primers that detect a segment of the 18S rRNA gene of the Babesia genus. Amplicons of the expected size for B. gibsoni were observed in 4 of the 16 dogs. The sequence of the 18S rRNA yield a 460 base pair segment that had a 99% homology with the B. gibsoni genotype Asia 1. Our findings suggest that the small piroplasm that naturally infects dogs in Brazil is B. gibsoni genotype Asia.