[Performance assessment employing slide sets: A tool for the classification of senior microscopists from Colombia´s Malaria Control Program]. / Evaluación del desempeño mediante paneles de láminas: una herramienta para la clasificación de los microscopistas sénior del Programa de Control de la Malaria en Colombia.

INTRODUCTION: One of the most important activities for quality assurance of malaria diagnosis is performance assessment. In Colombia, performance assessment of malaria microscopists has been done through the external performance assessment and indirect external performance assessment programs. OBJECTIVES: To assess the performance of malaria microscopists of public reference laboratories using slide sets, and to describe the methodology used for this purpose. MATERIALS AND METHODS: This was a retrospective study to evaluate the concordance of senior microscopists regarding parasite detection, species identification and parasite count based on the results of the assessment of competences using two sets, one comprising 40 slides, and another one with 17 slides. RESULTS: The concordance for parasite detection was 96.9% (95% CI: 96.0-97.5) and 88.7% (95% CI: 86.6-90.5) for species identification. The average percentage of concordant slides in the group evaluated was 89.7% (95% CI: 87.5-91.6). CONCLUSIONS: Most of the senior microscopists in Colombia were classified in the two top categories in the performance assessment using slide sets. The most common difficulty encountered was the identification of parasite species. The use of this tool to assess individual performance of microscopists in the evaluation of samples with different degrees of difficulty allows for characterizing the members of the malaria diagnosis network and strengthening the abilities of those who require it.

Wide-field fluorescent microscopy on a cell-phone.

We demonstrate wide-field fluorescent imaging on a cell-phone, using compact and cost-effective optical components that are mechanically attached to the existing camera unit of the cell-phone. Battery powered light-emitting diodes (LEDs) are used to side-pump the sample of interest using butt-coupling. The pump light is guided within the sample cuvette to excite the specimen uniformly. The fluorescent emission from the sample is then imaged with an additional lens that is put in front of the existing lens of the cell-phone camera. Because the excitation occurs through guided waves that propagate perpendicular to the detection path, an inexpensive plastic color filter is sufficient to create the dark-field background needed for fluorescent imaging. The imaging performance of this light-weight platform (~28 grams) is characterized with red and green fluorescent microbeads, achieving an imaging field-of-view of ~81 mm(2) and a spatial resolution of ~10 µm, which is enhanced through digital processing of the captured cell-phone images using compressive sampling based sparse signal recovery. We demonstrate the performance of this cell-phone fluorescent microscope by imaging labeled white-blood cells separated from whole blood samples as well as water-borne pathogenic protozoan parasites such as Giardia Lamblia cysts.

PCR for diagnosis and assessment of cure in kala-azar patients in Bangladesh.

The study evaluated the usefulness of Leishmania-nested polymerase chain reaction (Ln-PCR) for diagnosis of kala-azar and assessed its role as a test of cure among kala-azar patients in Bangladesh. Peripheral blood buffy coat Ln-PCR was done in ninety-seven (97) clinically suspected patients of kala-azar, in forty (40) healthy controls from both endemic and non-endemic areas, and in forty-six (46) patients after completion of treatment with sodium stibogluconate (SSG). The Ln-PCR results were compared with Leishmania donovani parasite load graded by 1+ to 6+ in all smear-positive L. donovani cases. Out of 97 clinically suspected kala-azar patients, 94 were parasitologically confirmed. Ln-PCR was found positive in 91 of 94 parasitologically positive patients of kala-azar at diagnosis, indicating its diagnostic sensitivity as 97%. None of the controls was found positive for Ln-PCR, indicating its diagnostic specificity to be 100%. About 9% of kala-azar patients having been graded 1+ parasitic load had negative Ln-PCR results. After completion of treatment, Ln-PCR was positive in 4 patients (8.4%) out of 46 cases, indicating its role in demonstrating the absence of parasites 30 days after completion of treatment in 91.6% of the treated patients. This limited study suggests that Ln-PCR is a highly sensitive and specific test for the diagnosis of visceral leishmaniasis and can be used as a test of cure. Thus, efforts should be made to establish this useful method at least in the tertiary care hospitals and, if possible, at the district-level hospitals, especially in the endemic areas of Bangladesh.

Research on the schizont cell culture vaccine against Theileria annulata infection in Xinjiang, China.

Theileria annulata infection (TAI) is one of the most serious diseases of cattle in Xinjiang Autonomous Region of Uigur Minority Nationality. It has been recorded in 14 prefectures, except the Tulufan Prefecture, but the enzootic areas are mainly distributed around the Zhunger Basin and Talim Basin. According to the records collected in the ten years before vaccination with the schizont cell culture vaccine was carried out, the average incidence rate of TAI in enzootic areas was 7.22% and the mortality rate was 24%. The milk production of cattle suffering from TAI was sharply decreased, and there were usually abortions in pregnant cows. The incidence rate and mortality rate were greater in high grade cattle, so TAI was a constraint to improving cattle breeds. To control this disease effectively in Xinjiang, researchers at the Xinjiang Academy of Animal Science began to study the schizont cell culture vaccine in 1972. In 1977 an immortalised cell line was achieved from a primary cell culture starting with white blood cells from cattle suffering from acute TAI caused by an artificial tick bite. The cell culture medium mainly consisted of calf serum, lactalbumin-hydrolysate, Eagles' medium DMEM and three antibiotics. As a vaccine, the above cells were mixed with preserving medium containing gelatin. This paper describes the experiments on the immunological properties of the vaccine carried out in subsequent years. Up to 1996, vaccine doses for 1,186,150 cattle have been produced and sold. This vaccine has had a critical effect on the control of TAI in Xinjiang. Owing to the sharp decrease in the incidence rate and mortality rate of TAI after cattle were vaccinated, the annual economic benefit of the vaccine is at least 1,620,000 yuan.