Combatting Global Infectious Diseases: A Network Effect of Specimen Referral Systems.

The recent Ebola virus outbreak in West Africa clearly demonstrated the critical role of laboratory systems and networks in responding to epidemics. Because of the huge challenges in establishing functional laboratories at all tiers of health systems in developing countries, strengthening specimen referral networks is critical. In this review article, we propose a platform strategy for developing specimen referral networks based on 2 models: centralized and decentralized laboratory specimen referral networks. These models have been shown to be effective in patient management in programs in resource-limited settings. Both models lead to reduced turnaround time and retain flexibility for integrating different specimen types. In Haiti, decentralized specimen referral systems resulted in a 182% increase in patients enrolling in human immunodeficiency virus treatment programs within 6 months. In Uganda, cost savings of up to 62% were observed with a centralized model. A platform strategy will create a network effect that will benefit multiple disease programs.

Strengthening national laboratory health systems in the Caribbean Region.

The President's Emergency Plan for AIDS Relief (PEPFAR) programme for the Caribbean Region was established in 2008 to address health system challenges, including fragile laboratory services and systems. The laboratory component of this programme consisted of several phases: assessment of laboratory needs of all 12 countries engaged in the programme; addressing gaps identified during the assessment; and monitoring and evaluation of the progress achieved. After one year of PEPFAR collaboration with national governments and other partners, laboratory services and systems greatly improved. Some of the milestones include: (1) the accreditation of a public laboratory; (2) improved access to HIV diagnosis with faster turnaround time; (3) establishment of capacity for platforms for DNA PCR, viral load and HIV drug resistance; (4) development of the laboratory workforce; and (5) establishment of a framework for implementation of sustainable quality management systems for laboratory accreditation. The progress recorded in strengthening laboratory health systems after one year of initiating this collaboration shows that with a rigorous initial assessment, programme design and intervention and strategic partnership, national laboratory health systems can be greatly enhanced to support programme implementation. Continued collaboration and country leadership is critical to create an integrated and sustainable laboratory network in the Caribbean.

Prevalence of drug resistance-related polymorphisms in treatment-naive individuals infected with nonsubtype B HIV type 1 in Cameroon.

Mutations associated with the use of protease (PR) and reverse transcriptase (RT) inhibitors have been mostly mapped for HIV-1 subtype B. The prevalence of these mutations in drug-naive HIV-1 subtype B-infected individuals is low but occurs at high frequencies in treated individuals. To determine the prevalence of treatment-associated mutations in non-B viruses, we analyzed a 1613-bp pol region of specimens collected from 57 HIV-1-infected treatment-naive individuals from Cameroon. Of the 57 HIV-1 sequences, 43 belonged to CRF02-AG, two to CRF11-cpx, six to subtype A, one to subtype D, and five were unclassifiable. Of the 57 PR sequences, 100% contained at least one codon change giving substitutions at positions 10, 11, 16, 20, 33, 36, 60, 62, 64, 69, 77, and 89. These substitutions gave the following prevalence pattern, 36I/L (100%, 57/57) >89M/I (98%, 56/57)>69K/R (93%, 53/57)>20I/R (89%, 51/57)>16E (16%, 9/57)>64M (12%, 7/57)>10I (11%, 6/57)>11V (5%, 3/57)=62V (5%, 3/57)=77I (5%, 3/57)>233F/V (4%, 2/57)=60E (4%), which differed significantly from subtype B at positions 20, 36, 69, and 89. All but one (98%) of the 57 RT sequences (438 amino acid residues) carried substitutions located at codons 39A (7%), 43E (7%), 122E (7%), 312Q (2%), 333E (2%), 335C/D (89%), 356K (89%), 358K (14%), 365I (2%), 371V (81%), 376S (11%), or 399D (4%); the frequency of these substitutions ranged from <0.5% to 4% in RT of subtype B. The high prevalence of minor mutations associated with protease inhibitors (PI) and reverse transcriptase inhibitors (RTI) represents natural polymorphisms. HIV-1 PR and RT sequences from antiretroviral (ARV)-naive HIV-infected persons in Cameroon are important for monitoring the development of resistance to PIs and RTIs as such mutations could lead to treatment failures in individuals undergoing ARV therapy.

Field evaluation of Calypte's AWARE blood serum plasma (BSP) and oral mucosal transudate (OMT) rapid tests for detecting antibodies to HIV-1 and 2 in plasma and oral fluid.

As programs to prevent and care for HIV-infected persons are scaled-up in Africa, there is the need for continuous evaluation of the performance of test kits that could best support these programs. The present study evaluated the sensitivity, specificity, ease of use, and cost of AWARE Blood Serum Plasma (BSP) and Oral Mucosal Transudate (OMT) Rapid HIV-1/2 test kits using real-time and archived samples of HIV-infected persons from Cameroon. Matched whole blood and OMT specimens were collected prospectively from HIV-positive and HIV-negative persons from different regions of Cameroon and tested using the AWARE BSP and OMT test kits, respectively. These results were compared to the gold standard that included a combination of Determine HIV-1/2 and Enzygnost HIV-1/2. The BSP Rapid test kit was further evaluated using well characterized panels of HIV-2 and HIV-1 group O samples. Cost and end-user analysis of the OMT test kit was done by comparing its actual cost, consumables, safety, bench time and manipulation with other test kits. Of the 732 matched samples, 412 (56.3%) and 320 (43.7%) were from females and males, respectively. Of these samples, 23 (3.1%) gave discordant results between Determine HIV-1/2 and Enzygnost HIV1/2 and were excluded from the analysis. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the AWARE BSP were 100%. The AWARE OMT had 98.8% sensitivity, 98.9% specificity, 98.0% PPV and 99.4% NPV. The results of a well-characterized archived panel of HIV-2 (n=7) and HIV-1 group O (n=3) samples using the AWARE BSP Rapid test kit gave 100% concordance. Total per patient cost of the AWARE OMT rapid test kit was US dollars 4.72 compared to a mean cost of US dollars 7.33 +/- 0.11 for the other test kits. Both the AWARE BSP and OMT Rapid test kits demonstrated high sensitivities and specificities on all samples tested and were well adapted for use in resource-constrained settings with high HIV heterogeneity such as Cameroon. The AWARE HIV-1/2 OMT Rapid test kit appears to be the cheapest, safest and easiest to use compared with other available test kits.

Human immunodeficiency virus type 1 group m protease in cameroon: genetic diversity and protease inhibitor mutational features.

To establish a baseline for monitoring resistance to protease inhibitors (PIs) and examining the efficacy of their use among persons in Cameroon infected with human immunodeficiency virus type 1 (HIV-1), we analyzed genetic variability and PI resistance-associated substitutions in PCR-amplified protease (PR) sequences in strains isolated from 110 HIV-1-infected, drug-naïve Cameroonians. Of the 110 strains, 85 were classified into six HIV-1 PR subtypes, A (n = 1), B (n = 1), F (n = 4), G (n = 7), H (n = 1), and J (n = 7), and a circulating recombinant form, CRF02-AG (n = 64). PR genes from the remaining 25 (23%) specimens were unclassifiable, whereas 2% (7 of 301) unclassifiable PR sequences were reported for a global collection. Two major PI resistance-associated mutations, 20M and 24I, were detected in strains from only two specimens, whereas secondary mutations were found in strains from all samples except one strain of subtype B and two strains of CRF02-AG. The secondary mutations showed the typical PI resistance-associated pattern for non-subtype B viruses in both classifiable and unclassifiable PR genes, with 36I being the predominant (99%) mutation, followed by 63P (18%), 20R (15%), 77I (13%), and 10I or 10V (11%). Of these mutations, dual and triple PI resistance-associated substitutions were found in 38% of all the Cameroonian strains. Compared with classifiable PR sequences, unclassifiable sequences had significantly more dual and triple substitutions (64% versus 30%; P = 0.004). Phenotypic and clinical evaluations are needed to estimate whether PI resistance during antiretroviral drug treatment occurs more rapidly in individuals infected with HIV-1 strains harboring multiple PI resistance-associated substitutions. This information may be important for determination of appropriate drug therapies for HIV-1-infected persons in Cameroon, where more than one-third of HIV-1 strains were found to carry dual and triple minor PI resistance-associated mutations.