Evaluation of a Diagnostic Algorithm Using Immunoglobulin M Enzyme-Linked Immunosorbent Assay To Differentiate Human West Nile Virus and St. Louis Encephalitis Virus Infections during the 2002 West Nile Virus Epidemic in the United States

A diagnostic algorithm was developed to differentiate between human infections of West Nile virus (WNV) and St. Louis encephalitis virus (SLEV) using positive-to-negative (P/N) ratios derived from the immunoglobulin M capture enzyme-linked immunosorbent assay (MAC-ELISA). To validate this algorithm, we tested 1,418 serum and cerebrospinal fluid (CSF) samples from confirmed WNV and SLEV infections collected during the WNV epidemic of 2002 in the United States. WNV P/N-to-SLEV P/N ratios (W/S ratios) were calculated and used to identify the infecting virus. These results were compared to results from the plaque reduction neutralization test (PRNT), which is currently the standard assay used to discriminate between closely related flavivirus infections. If the W/S ratio was ≥1, the predictive value positive (PNP) for WNV was 97.8%, where 95% of flavivirus cases were due to WNV infection and only 3.7% of specimens would require PRNT to differentiate WNV from SLEV infection. Use of the W/S ratio as part of the testing algorithm to interpret MAC-ELISA results generates reportable probable cases quickly, alleviating the need for PRNT in most instances.     

Detection of Rickettsia felis in a New World flea species, Anomiopsyllus nudata (Siphonaptera: Ctenophthalmidae)

The flea and rodent samples studied in this project were collected from field study sites in New Mexico from winter 1998 to spring 2001. During this period, 155 small rodents (14 different species) were live-trapped and combed for the presence of fleas. A total of 253 fleas were collected, comprising 21 species. Two of the 253 fleas collected were polymerase chain reaction (PCR) positive for the Rickettsia 17-kDa protein gene. These two fleas were both Anomiopsyllus nudata Baker, each collected from an individual Neotoma albigula Hartley, on two occasions. Individual fleas positive for the Rickettsia 17-kDa protein gene were then tested with primers targeting the rickettsial genes for citrate synthase (gltA) and two major outer membrane proteins (ompA and ompB). The nucleotide sequences of the PCR products of these two fleas were identical to each other and were 100% (394/394), 100% (1150/1150), 99.8% (469/470), and 99.3% (818/824) similar to the corresponding sequences of the 17-kDa, gltA, ompA, and ompB genes of Rickettsia felis, respectively. Flea homogenates of individual PCR-positive fleas were inoculated into shell vials seeded with Vero cells, and the Gimenez stain technique was used to demonstrate the presence of Rickettsia-like organisms in detached cells found in aspirated medium 19 d after inoculation. These cells were harvested and tested by PCR, targeting portions of the 17-kDa and gltA genes, resulting in products 100% identical to R. felis. This work comprises the first report of R. felis detection in a flea species (A. nudata) endemic to the New World.     

Risk Factors for Human Lice and Bartonellosis among the Homeless,San Francisco,California, USA

Homeless persons in San Francisco, California, USA, have been shown to have head and body lice infestations and Bartonella quintana infections. We surveyed a self-selected population of homeless persons in San Francisco to assess infestations of head and body lice, risks of having body lice, and presence of B. quintana in lice. A total of 203 persons who reported itching were surveyed during 2008–2010 and 2012: 60 (30%) had body lice, 10 (4.9%) had head lice, and 6 (3.0%) had both. B. quintana was detected in 10 (15.9%) of 63 body lice pools and in 6 (37.5%) of 16 head lice pools. Variables significantly associated (p<0.05) with having body lice in this homeless population included male sex, African–American ethnicity, and sleeping outdoors. Our study findings suggest that specific segments of the homeless population would benefit from information on preventing body lice infestations and louseborne diseases.     

Prognostic significance of pathological and biological factors in hepatocellular carcinoma

Prognostic factors in hepatocellular carcinoma (HCC) conventionally consist of staging with the tumour node metastasis system and grading by tumour cellular differentiation. There are also other factors useful in prognostication but most of them are clinical. With new discoveries in the pathobiology of cancers and introduction of new medical technology, pathological and biological factors of HCC in relation to prognosis have been studied quite extensively. Morphological features of the tumour, both gross and histological, have been found to be significantly related to tumour recurrence and patient survival. Recently, applications of new antibodies and techniques have enabled studies on cellular proliferation using different antibodies such as those for proliferating cell nuclear antigen and Ki-67 protein. These studies on cellular proliferation, as well as assessment of argyrophilic nucleolar organizing regions, have been shown to provide good prognostic significance. Flow cytometric studies on DNA ploidy and studies on expression of genes including the p53 gene, hormone receptors and others show less unanimous results in their prognostic significance. The influence of gender on survival is also reviewed. In conclusion, pathological and biological factors are useful and help to guide clinicians in the management of patients and in assessment of long-term prognosis.     

Prognostic importance of soluble CD23 in B‐cell chronic lymphocytic leukemia

Soluble CD23 (sCD23) was proposed as a marker of disease activity and as an important prognostic parameter in B‐cell chronic lymphocytic leukemia (B‐CLL). In this study, prognostic significance of sCD23 in B‐CLL was examined according to its temporal relationship with the known clinical parameters of the disease, CD38 and ZAP‐70. Serum sCD23 levels of 36 B‐CLL patients, followed up in our clinic between 1999 and 2005, and 15 healthy subjects were measured with enzyme‐linked immunosorbent assay. The mean serum sCD23 level of the B‐CLL patients (210.72 ± 193.67 and 6–600 U/ml) was significantly higher than the control group (18.20 ± 14.30 and 6–50 U/ml). Seventy‐eight percent of the B‐CLL patients with lymphocyte doubling time (LDT) <12 months and 24% of patients with LDT >12 months had high sCD23 levels (P = 0.008). Meanwhile, 81% of the patients with diffuse bone marrow infiltration and 33% of patients with nondiffuse infiltration had high levels of serum sCD23 (P = 0.029). A significant difference was found between B‐CLL patients with Binet stages A and C (P = 0.009). Peripheral blood flow cytometry of the patients revealed a significant CD38 expression in patients with high serum sCD23 levels (P = 0.002). Similarly, an increased bone marrow zeta‐chain associated protein kinase‐70 (ZAP‐70) expression was seen in patients with high serum sCD23 levels (P = 0.009, correlation co‐efficient was 0.714). Cumulative and the progression free survivals of the patients with low serum sCD23 levels were 60.1 ± 5.7 months [95% confidence interval (CI); 49.0–71.2] and 51.1 ± 6.6 months (95% CI; 38.0–64.1), respectively. However, they were 43.8 ± 6.5 months (95% CI; 31.0–56.6) and 26.5 ± 6.4 months (95% CI; 14.0–39.1) in patients with high levels. Serum sCD23 is increased in B‐CLL patients and can be used in the clinical follow‐up of the disease in prediction of the tumor mass and prognosis.     

Combining culture techniques for Bartonella: the best of both worlds

In this study we compared some common Bartonella culturing methodologies using four diverse species causing human illnesses. Based on a review of the literature, we focused on three major inconsistencies between protocols: base medium, cell coculture, and temperature. Our data showed that Bartonella tamiae demonstrated temperature-dependent growth limitations between common culturing conditions only 2°C apart. Additionally, growth of B. quintana was significantly enhanced by the presence of mammalian cell coculture under mammalian cell culture conditions; however, when the medium was modified to incorporate insect cell culture-based medium, coculturing with mammalian cells was no longer needed. In this study, we were able to overcome these temperature- and cell-dependent limitations and accommodate all of the strains tested by combining mammalian cell culture-based medium with insect cell culture-based medium.     

Ancestry informative marker sets for determining continental origin and admixture proportions in common populations in America

To provide a resource for assessing continental ancestry in a wide variety of genetic studies, we identified, validated, and characterized a set of 128 ancestry informative markers (AIMs). The markers were chosen for informativeness, genome-wide distribution, and genotype reproducibility on two platforms (TaqMan assays and Illumina arrays). We analyzed genotyping data from 825 subjects with diverse ancestry, including European, East Asian, Amerindian, African, South Asian, Mexican, and Puerto Rican. A comprehensive set of 128 AIMs and subsets as small as 24 AIMs are shown to be useful tools for ascertaining the origin of subjects from particular continents, and to correct for population stratification in admixed population sample sets. Our findings provide general guidelines for the application of specific AIM subsets as a resource for wide application. We conclude that investigators can use TaqMan assays for the selected AIMs as a simple and cost efficient tool to control for differences in continental ancestry when conducting association studies in ethnically diverse populations.     

Human isolates of <Emphasis Type="Italic">Bartonella tamiae</Emphasis>induce pathology in experimentally inoculated immunocompetent mice

Background  

Bartonella tamiae, a newly described bacterial species, was isolated from the blood of three hospitalized patients in Thailand. These patients presented with headache, myalgia, anemia, and mild liver function abnormalities. Since B. tamiae was presumed to be the cause of their illness, these isolates were inoculated into immunocompetent mice to determine their relative pathogenicity in inducing manifestations of disease and pathology similar to that observed in humans.