Anaplasmosis in Uganda. I. Use of dried blood on filter papers and serum samples for serodiagnosis of anaplasmosis--a comparative study

The suitability of blood collected on filter papers in comparison with corresponding conventional serum samples in the diagnosis of bovine anaplasmosis was studied using the complement fixation test; DOT-ELISA; Western immunoblot and rapid card agglutination test. Dried blood on Whatman filter paper no. 1 was eluted in PBS 0.05pc Tween 20 giving an initial dilution of 1:10. The reactivity of the eluted samples in both DOT-ELISA and Western immunoblotting were similar to those obtained with the corresponding straight serum sample dilutions. Filter paper samples gave lower reactivity in the remaining tests when compared with corresponding serum samples. There was no significant difference in the reactivity between the eluates from filter papers stored at temperatures ranging between 15.5 and 24 degrees C and those kept refrigerated. Storage at 15.5 to 24 degrees C did not significantly affect reactivity for up to six months. Eluates from filter papers stored for six months at 15.5 to 24 degrees C continued to give similar reactivity as those from freshly prepared filter papers in both DOT-ELISA and Western blot; and in the rapid card agglutination test. It is concluded that collecting blood on filter papers is a suitable technique for large scale seroepidemiological studies on anaplasmosis and offers many advantages in developing countries where transport and cold chain facilities are a major constraint

The value of a clinical definition for epidemic KS in predicting HIV seropositivity in Africa

Kaposi's sarcoma (KS) in African adults can present in endemic (non-HIV-related) and epidemic (HIV-related) forms. We evaluated the usefulness of a clinical case definition for epidemic KS in predicting HIV seropositivity. A total of 235 patients with KS presenting to the Uganda Cancer Institute from January 1; 1988 to March 31; 1990 were evaluated with history and physical examination. Symptomatic patients underwent chest radiography and upper gastrointestinal endoscopy. One hundred seventy-four patients (80pc) underwent HIV ELISA testing with Western blot confirmation. The clinical case definition had a 91pc sensitivity and a 95pc specificity in predicting HIV seropositivity. Oral KS was the most sensitive specific site of involvement in predicting HIV seropositivity. The clinical case definition is useful in assessing patients to determine prognosis and likelihood of responding to aggressive therapy

Non-isotopic polymerase chain reaction methods for the detection of HIV-1 in Ugandan mothers and infants

Two non-isotopic polymerase chain reaction (PCR) methods were evaluated by testing blood from 41 HIV-1-seropositive and 16 HIV-1-seronegative Ugandan mothers and 56 of their children (aged 0.5-15.0 months). Amplification of HIV-1 sequences was performed in duplicate using a biotinylated primer pair to the gag region (SK 462-431) and nested primer pairs (JA 17-20) to the pol region of HIV-1. gag sequences were hybridized using a microtiter plate coated with the SK 102 probe followed by colorimetric detection using an avidin-horseradish peroxidase conjugate and tetramethylbenzidine/peroxide substrate. pol sequences were detected on agarose gel stained with ethidium bromide. Results of HIV-1 PCR analysis showed that 40 out of 41 (98pc) seropositive mothers and 10 out of 29 (34pc) seropositive children had detectable HIV-1 gag and pol sequences. None of the 16 seronegative mothers nor 27 seronegative or Western blot-indeterminate children had detectable HIV-1 sequences. Our results suggest that non-isotopic PCR methods are sensitive; specific; and potentially useful in the early diagnosis of HIV-1 infection in developed and developing countries

Seroepidemiology of HIV infection: an early survey in a peripheral area of Uganda

At the end of 1985; when the AIDS epidemic was in its early stages in Uganda; a survey was carried out in a peripheral area of the country. Sera were collected from groups of people; and examined for the presence of HIV infection. The results show a very limited number of positive cases; present only among sexually active subjects. High specificity and sensitivity in the laboratory tests was shown by the Western blot technique

Anaplasmosis in Uganda. II. Prevalence of bovine anaplasmosis in Uganda

The prevalence of bovine anaplasmosis was studied in 320 Zebu cattle randomly selected from three regions of Uganda: (Central; Southwestern and Northwestern) using dot-ELISA; Western immunoblotting; rapid card agglutination test (RCAT); capillary tube agglutination test (CAT); complement fixation test (CFT); and parasitological techniques. Dried blood on Whatman filter paper No. 1 was eluted in PBS 0.05pc Tween 20 prior to testing at an initial dilution of 1:25. The prevalences of parasitaemia were 25pc in the central region; 28pc in the southwestern region; and 35pc in the northwestern region; and the serological prevalence was lowest in the central region and highest in the northwest. Overall; prevalence rates obtained by dot-ELISA (61.9pc) and Western immunoblotting (62.5pc) were 1.5 times those obtained by RCAT (41pc) and three times those obtained by CAT (22.5pc). The overall prevalence rates obtained by dot-ELISA and Western immunoblotting compared favourably with the CFT data. The present data utilizing dried blood on filter papers indicate that there is a high prevalence of anaplasmosis in those regions of Uganda surveyed; and confirm our observations and those of others that collecting blood on filter papers is a suitable technique for large scale screening and for seroepidemiological studies