Likely female-to-female sexual transmission of HIV--Texas, 2012.

In August 2012, the Houston Department of Health contacted CDC regarding the rare transmission of human immunodeficiency virus (HIV) likely by sexual contact between two women. The case was investigated, and laboratory testing confirmed that the woman with newly diagnosed HIV infection had a virus virtually identical to that of her female partner, who was diagnosed previously with HIV and who had stopped receiving antiretroviral treatment in 2010. This report describes this case of HIV infection, likely acquired by female-to-female sexual transmission during the 6-month monogamous relationship of the HIV-discordant couple (one negative, one positive). The woman with newly acquired infection did not report any other recognized risk factors for HIV infection, and the viruses infecting the two women had ≥ 98% sequence identity in three genes. The couple had not received any preventive counseling before acquisition of the virus by the woman who had tested negative for HIV. HIV-discordant couples should receive counseling regarding safer sex practices, and HIV-infected partners should be linked to and retained in medical care.

Comparison of Babesia microti Real-Time Polymerase Chain Reaction Assays for Confirmatory Diagnosis of Babesiosis.

Babesiosis is an emerging tick-borne disease caused by apicomplexan parasites of the genus Babesia Most human infections in the United States are caused by Babesia microti, but other infection-causing Babesia parasites have been documented as well. Polymerase chain reaction (PCR)-based methods can be used to identify this parasite to the species level. In this study, published real-time PCR assays for the specific detection of B. microti were evaluated against conventional PCR for their analytical performance. All evaluated real-time PCR assays had comparable dynamic range and amplification efficiency, but the sensitivity and specificity varied. The best performing test, a TaqMan assay targeting the 18S ribosomal RNA gene, was further evaluated for diagnostic performance using blood specimens submitted to the Centers for Disease Control and Prevention for parasite detection and was found to have 100% sensitivity and specificity. In conclusion, the 18S TaqMan real-time PCR assay is a sensitive, specific, and rapid method for identification of B. microti among cases of babesiosis in the United States.

Dual Simian Foamy Virus/Human Immunodeficiency Virus Type 1 Infections in Persons from Côte d'Ivoire.

Zoonotic transmission of simian retroviruses in West-Central Africa occurring in primate hunters has resulted in pandemic spread of human immunodeficiency viruses (HIVs) and human T-lymphotropic viruses (HTLVs). While simian foamy virus (SFV) and simian T- lymphotropic virus (STLV)-like infection were reported in healthy persons exposed to nonhuman primates (NHPs) in West-Central Africa, less is known about the distribution of these viruses in Western Africa and in hospitalized populations. We serologically screened for SFV and STLV infection using 1,529 specimens collected between 1985 and 1997 from Côte d'Ivoire patients with high HIV prevalence. PCR amplification and analysis of SFV, STLV, and HIV/SIV sequences from PBMCs was used to investigate possible simian origin of infection. We confirmed SFV antibodies in three persons (0.2%), two of whom were HIV-1-infected. SFV polymerase (pol) and LTR sequences were detected in PBMC DNA available for one HIV-infected person. Phylogenetic comparisons with new SFV sequences from African guenons showed infection likely originated from a Chlorocebus sabaeus monkey endemic to Côte d'Ivoire. 4.6% of persons were HTLV seropositive and PCR testing of PBMCs from 15 HTLV seroreactive persons identified nine with HTLV-1 and one with HTLV-2 LTR sequences. Phylogenetic analysis showed that two persons had STLV-1-like infections, seven were HTLV-1, and one was an HTLV-2 infection. 310/858 (53%), 8/858 (0.93%), and 18/858 (2.1%) were HIV-1, HIV-2, and HIV-positive but undifferentiated by serology, respectively. No SIV sequences were found in persons with HIV-2 antibodies (n = 1) or with undifferentiated HIV results (n = 7). We document SFV, STLV-1-like, and dual SFV/HIV infection in Côte d'Ivoire expanding the geographic range for zoonotic simian retrovirus transmission to West Africa. These findings highlight the need to define the public health consequences of these infections. Studying dual HIV-1/SFV infections in immunocompromised populations may provide a new opportunity to better understand SFV pathogenicity and transmissibility in humans.

Performance evaluation of the CHEMBIO DPP® (dual path platform) HIV-1/2 assay in early and established infections.

BACKGROUND: The availability of more accurate point-of-care technology could increase the number of persons aware of their HIV status. The DPP(®) HIV-1/2 assay is the first dual path platform rapid test (RT) approved in the U.S. that also received the Clinical Laboratory Improvement Amendments (CLIA) waiver for use with oral fluid and fingerstick and venous whole blood. OBJECTIVE: To evaluate the performance of the DPP(®) HIV-1/2 assay with plasma specimens. STUDY DESIGN: Sensitivity and specificity of the assay were calculated from 696 HIV-1 groups M (B and non-B subtypes) and O and HIV-2 (groups A and B) specimens and 505 HIV-negative specimens, respectively. Analysis of the assay performance in HIV-1 early infections was assessed by estimating the relative sensitivity of the RT before the Western blot (WB) becomes positive using a 50% cumulative frequency analysis and by comparing the reactivity with other Food and Drug Administration (FDA)-approved RTs. RESULTS: The sensitivity for established infection was 100% for HIV-1 and 100% for HIV-2. The specificity was 100%. The DPP(®) HIV-1/2 assay performs similarly to most antibody-based RT approved by FDA in early HIV-1 infections. CONCLUSIONS: The DPP(®) technology showed no significant improvement for detecting early infections over other lateral-flow RTs used in the U.S. Without more data on the DPP(®) HIV-1/2 assay, especially from whole blood and oral fluid specimens collected during the early phase of infection, its performance as point-of-care technology remains to be assessed.

Evaluation of the CDC proposed laboratory HIV testing algorithm among men who have sex with men (MSM) from five US metropolitan statistical areas using specimens collected in 2011.

BACKGROUND: Until recently most testing algorithms in the United States (US) utilized Western blot (WB) as the supplemental test. CDC has proposed an algorithm for HIV diagnosis which includes an initial screen with a Combo Antigen/Antibody 4th generation-immunoassay (IA), followed by an HIV-1/2 discriminatory IA of initially reactive-IA specimens. Discordant results in the proposed algorithm are resolved by nucleic acid-amplification testing (NAAT). OBJECTIVES: Evaluate the results obtained with the CDC proposed laboratory-based algorithm using specimens from men who have sex with men (MSM) obtained in five metropolitan statistical areas (MSAs). STUDY DESIGN: Specimens from 992 MSM from five MSAs participating in the CDC's National HIV Behavioral Surveillance System in 2011 were tested at local facilities and CDC. The five MSAs utilized algorithms of various screening assays and specimen types, and WB as the supplemental test. At the CDC, serum/plasma specimens were screened with 4th generation-IA and the Multispot HIV-1/HIV-2 discriminatory assay was used as the supplemental test. NAAT was used to resolve discordant results and to further identify acute HIV infections from all screened-non-reactive missed by the proposed algorithm. Performance of the proposed algorithm was compared to site-specific WB-based algorithms. RESULTS: The proposed algorithm detected 254 infections. The WB-based algorithms detected 19 fewer infections; 4 by oral fluid (OF) rapid testing and 15 by WB supplemental testing (12 OF and 3 blood). One acute infection was identified by NAAT from all screened-non-reactive specimens. CONCLUSIONS: The proposed algorithm identified more infections than the WB-based algorithms in a high-risk MSM population. OF testing was associated with most of the discordant results between algorithms. HIV testing with the proposed algorithm can increase diagnosis of infected individuals, including early infections.

Performance of the Alere Determine™ HIV-1/2 Ag/Ab Combo Rapid Test with specimens from HIV-1 seroconverters from the US and HIV-2 infected individuals from Ivory Coast.

BACKGROUND: FDA-approved HIV Antigen/Antibody combo (4th generation) immunoassays (IAs) can identify HIV-1 infections before the Western blot (WB) becomes positive. In the US, increased detection of acute HIV infections has been facilitated by using 4th generation IAs, but there is no FDA-approved 4th generation rapid test (RT). The Alere Determine™ HIV-1/2 Ag/Ab Combo (Determine Combo) RT detects and distinguishes HIV p24 Antigen (Ag) from Antibody (Ab) to HIV-1+HIV-2 and thus has the potential to improve diagnosis of acute HIV infection. OBJECTIVE: To evaluate the ability of Determine Combo RT to detect acute/early HIV-1 infections and HIV-2 antibody in well-characterized plasma specimens. STUDY DESIGN: In HIV-1 seroconverters from the US, Determine Combo reactivity was evaluated by performing the 50% cumulative frequency analysis and by comparing with 3rd and 4th generation IAs' reactivity. HIV-2 plasma specimens from Ivory Coast were tested with Determine Combo. RESULTS: The 50% cumulative frequency analysis in 17 seroconverters placed Determine Combo (Ag+/Ab-, Ag+Ab+, Ag-/Ab+) and Ab-component reactivity at 15.5 and 7 days before WB positivity, respectively. In 26 seroconverters, Determine Combo was reactive in 99.0% and 92.5% of 3rd and 4th generation IAs-reactive specimens, respectively. All HIV-2 plasma specimens were Ab-reactive/Ag-non-reactive by Determine Combo. CONCLUSIONS: Based on previous results with the same seroconversion panels, combined Ag/Ab reactivity of the Determine Combo appears between FDA-approved 4th and 3rd generation laboratory IAs. These data indicate that this RT could detect HIV-1 infection earlier than other RTs and it performs well in HIV-2 specimens.

Evaluation of an alternative HIV diagnostic algorithm using specimens from seroconversion panels and persons with established HIV infections.

BACKGROUND: The current algorithm for HIV diagnosis in the US involves screening with an immunoassay (IA) and supplemental testing with Western blot (WB) or immunofluorescence assay. Because of existence of more sensitive and specific FDA-approved assays that would also reduce the cost and turn-around time of testing compared to WB, several alternative algorithms have been evaluated. Recently, an alternative algorithm using a sensitive 3rd or 4th generation IA followed by an HIV-1 and HIV-2 discriminatory supplemental test on the initial IA-positive specimens was proposed. Concordant positive results indicate HIV-positive specimens and discordant results are resolved by nucleic acid amplification testing (NAAT). OBJECTIVES: To evaluate the sensitivity of assays during acute HIV infection and the performance of the current and an alternative algorithm using samples from HIV-1 seroconversion panels and persons with established HIV infections. STUDY DESIGN: To evaluate the algorithms in early infections, 26 HIV-1 seroconverters from the US were tested with three 3rd generation and one 4th generation IA, six rapid tests (RTs), one NAAT, and WB. Sensitivity and specificity of the algorithms were calculated by testing an additional 416 HIV-positive and 414 uninfected control samples with one 3rd generation and one 4th generation IA, four RTs, one NAAT, and WB. RESULTS: The individual assays evaluated became positive 5 (RT) to 26 days (NAAT) before WB was positive. Among seroconverters, the alternative algorithm detected significantly more infections than the current algorithm (103-134 versus 56, p<0.0001). Furthermore, the use of a 4th generation IA instead of a 3rd generation assay as the screen resulted in significantly higher detection of acute infections (p<0.0001). In contrast, the algorithms performed equally among specimens from established HIV-1 infections. CONCLUSIONS: This study demonstrated improved sensitivity of the alternative algorithm for detecting acute HIV-1 infections, while maintaining the ability to accurately detect established HIV-1 infections. Early detection is important as individuals can be highly infectious during acute infection. In addition, the alternative algorithm should reduce turn-around time by using a RT as the supplemental test has the potential to increase the number of test results returned.