Multi-centre field evaluation of the performance of the Trinity Biotech Uni-Gold HIV 1/2 rapid test as a first-line screening assay for gay and bisexual men compared with 4th generation laboratory immunoassays

BACKGROUND

The Trinity Biotech Uni-Gold HIV test (Uni-Gold) is often used as a supplementary rapid test in testing algorithms.

OBJECTIVE

To evaluate the operational performance of the Uni-Gold as a first-line screening test among gay and bisexual men (GBM) in a setting where 4th generation HIV laboratory assays are routinely used.

STUDY DESIGN

We compared the performance of Uni-Gold with conventional HIV serology conducted in parallel among GBM attending 22 testing sites. Sensitivity was calculated separately for acute and established infection, defined using 4th generation screening Ag/Ab immunoassay (EIA) and Western blot results. Previous HIV testing history and results of supplementary 3rd generation HIV Ab EIA, and p24 antigen EIA were used to further characterise cases of acute infection.

RESULTS

Of 10,793 specimens tested with Uni-Gold and conventional serology, 94 (0.90%, 95%CI:0.70-1.07) were confirmed as HIV-positive by conventional serology, and 37 (39.4%) were classified as acute infection. Uni-Gold sensitivity was 81.9% overall (77/94, 95%CI:72.6-89.1); 56.8% for acute infection (21/37, 95%CI:39.5-72.9) and 98.2% for established infection (56/57, 95%CI:90.6-100.0). Of 17 false non-reactive Uni-Gold results, 16 were acute infections, and of these seven were p24 antigen reactive but antibody negative. Uni-Gold specificity was 99.9% (10,692/10,699, 95%CI:99.9-100.0), PPV was 91.7% (95%CI:83.6-96.6) and NPV was 99.8% (95%CI:99.7-99.9), respectively.

CONCLUSIONS

In this population, Uni-Gold had good specificity and sensitivity was high for established infections when compared to 4th generation laboratory assays, however sensitivity was lower in acute infections. Where rapid tests are used in populations with a high proportion of acute infections, additional testing strategies are needed to detect acute infections.

Effect of testing experience and profession on provider acceptability of rapid HIV testing after implementation in public sexual health clinics in Sydney

OBJECTIVES

Rapid HIV testing (RHT) is well established in many countries, but it is new in Australia since a policy change in 2011. We assessed service provider acceptability of RHT before and after its implementation in four Sydney public sexual health clinics.

METHODS

Service providers were surveyed immediately after training in RHT and again 6-12 months later. Differences in mean scores between survey rounds were assessed via t-tests, with stratification by profession and the number of tests performed.

RESULTS

RHT was rated as highly acceptable among staff at baseline and acceptability scores improved between survey rounds. Belief in being sufficiently skilled and experienced to perform RHT (P = 0.004) and confidence in the delivery of nonreactive results increased (P = 0.007), while the belief that RHT was disruptive declined (P = 0.001). Acceptability was higher for staff who had performed a greater number of tests regarding comfort with their role in RHT (P = 0.004) and belief that patients were satisfied with RHT (P = 0.007). Compared with nurses, doctors had a stronger preference for a faster rapid test (P = 0.027) and were more likely to agree that RHT interfered with consultations (P = 0.014).

CONCLUSIONS

Differences in responses between professions may reflect differences in staff roles, the type of patients seen by staff and the model of testing used, all of which may affect the number of tests performed by staff. These findings may inform planning for how best to implement RHT in clinical services.

The efficacy of TAMUS 2032 in preventing a natural outbreak of colibacillosis in broiler chickens in floor pens

A 42-d floor pen study was conducted with broiler chickens comparing the effects on bird performance of 12 ppm TAMUS 2032 (also known as BT) and 55 ppm bacitracin methylene disalicyclate (BMD) when fed alone or in combination with 99 ppm monensin (MON). Unmedicated and 99 ppm MON treatments were included in the study design. Beginning on d 22 of study, birds in all 6 treatments were subjected to a modulated house temperature and airflow to mimic conditions conducive to outbreaks of colibacillosis. A natural outbreak of colibacillosis developed beginning on d 27. Primary lesions in dead birds included airsacculitis and pericarditis with occasional findings of perihepatitis. At d 42 of study, means for weight gain in the TAMUS 2032 and TAMUS 2032 + MON treatments were greater in comparison with the unmedicated and BMD treatments, and means for feed conversion for both treatments were improved in comparison with the unmedicated treatment. Mean feed conversion in the TAMUS 2032 + MON treatment was also improved in comparison with BMD treatment. Mortality due to colibacillosis was reduced in the TAMUS 2032 (0.051%), TAMUS 2032 + MON (0.642%), and MON + BMD (1.515%) treatments in comparison with the unmedicated treatment (13.402%) and the BMD treatment (11.159%). The results of improved performance and reduced mortality indicated that 12 ppm TAMUS 2032 was highly efficacious against colibacillosis in growing chickens. The reduced mortality percentages in the MON + BMD treatment indicated that this combination also provided a good level of protection against the natural outbreak of colibacillosis.

World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines for evaluating the efficacy of anticoccidial drugs in chickens and turkeys

These guidelines have been written to aid in the design, implementation and interpretation of studies for the assessment of drug efficacy against Eimeria species in chickens and turkeys. The information provided deals with many aspects of how to conduct controlled studies in battery cages (dose determination), floor pens (dose confirmation), and commercial facilities (field effectiveness studies), the selection of birds, housing, feeding, preparation of medicated rations, record keeping, diagnostic techniques, and methods for the preparation, maintenance and use of parasites. These guidelines are also intended to assist investigators in conducting specific studies, provide specific information for registration authorities involved in the decision-making process, assist in the approval and registration of new anticoccidial drugs, and facilitate the world-wide adoption of standard procedures.

The use of diclazuril in extended withdrawal anticoccidial programs: 2. Immunity to Eimeria tenella challenge after drug withdrawal

The effect of diclazuril medication on the development of natural immunity to Eimeria tenella was determined. Birds in two treatments, nonexposed, non-challenged (NENC) and nonexposed, challenged (NEC), were from a holding group raised under conditions designed to prevent coccidial infection. Birds in five other treatments, from the same hatch and source as birds in the first two treatments, were from a floor pen study involving a natural exposure to Eimeria spp. These birds were assigned to the current study based on their respective treatments in the original floor pen study as follows: unmedicated (UNM), 66 ppm salinomycin (SAL) + 50 ppm roxarsone in the starter and grower diets to Day 28 (SAL 28), 66 ppm SAL + 50 ppm roxarsone in the starter diet and 1 ppm diclazuril (DIC) in the grower diet to Day 28 (DIC 28) or to Day 35 (DIC 35), or in the grower and finisher diets to Day 42 (DIC 42). Each treatment comprised three floor pens of 10 birds (female) in a randomized complete block design. All birds were fed an UNM finisher diet during the 7-d challenge study. Birds in each treatment, except NENC, were individually inoculated (p.o.) with 1 x 10(5) Eimeria tenella sporulated oocysts on Day 1. Based on bird performance and cecal lesion scores, birds in the DIC 35 and 42 treatments had a low immunity to the challenge infection, birds in the DIC 28 treatment were partially immunized, and the highest levels of immunity were observed in the UNM and SAL 28 treatments.

The use of diclazuril in extended withdrawal anticoccidial programs: 1. Efficacy against Eimeria spp. in broiler chickens in floor pens

A 49-d floor pen study was conducted with broiler chickens to compare the effects of different anticoccidial withdrawal times on the efficacy of 1 ppm diclazuril. The starter diet in three treatments contained 66 ppm salinomycin + 50 ppm roxarsone (3-nitro-4-hydroxyphenylarsonic acid), followed by 1 ppm diclazuril in the grower diet commencing on Day 17. Diclazuril was withdrawn from these treatments on Day 28, 35, or 42 (finisher diet), respectively. Two other treatments in the study were given 66 ppm salinomycin + 50 ppm roxarsone in the starter and grower diets to Day 28 or no anticoccidial (unmedicated). The starter (Days 0 to 16), grower (Days 17 to 35), and finisher (Days 36 to 49) diets in each treatment included 55 ppm bacitracin methylene disalicylate for growth promotion. Fifty 1-d-old chicks were randomly allotted to each of 10 pens per treatment using a randomized complete block design. Birds in each pen were raised on litter naturally contaminated with a mixture of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. The results demonstrated that some performance loss occurred in the salinomycin Day 28 treatment. Means for weight gain and feed conversion on Day 49 were improved (P < 0.05) in each diclazuril treatment in comparison with the salinomycin and unmedicated treatments. Feed conversion means in the diclazuril Day 35 and Day 42 treatments were improved (P < 0.05) in comparison with the diclazuril Day 28 treatment, indicating that shorter withdrawal times provided further benefit.

Efficacy of diclazuril in comparison with chemical and ionophorous anticoccidials against Eimeria spp. in broiler chickens in floor pens

Two 42-d floor pen studies were conducted with commercial broiler chickens to measure the efficacy of 1 ppm diclazuril in the starter or grower diet in shuttle programs with 66 ppm salinomycin. Study 1 compared a salinomycin to diclazuril (starter to grower diet) shuttle treatment with salinomycin to salinomycin, salinomycin to 100 ppm monensin, salinomycin to 99.8 ppm lasalocid, and unmedicated treatments. Study 2 compared a diclazuril to salinomycin (starter to grower) shuttle treatment with 125 ppm nicarbazin to salinomycin, 79.2 ppm narasin + nicarbazin to salinomycin, 125 ppm zoalene to salinomycin, and unmedicated treatments. Fifty 1-d-old chicks were randomly allotted to each of 10 pens per treatment in each study using a randomized complete block design. Starter (Days 0 to 21) and grower (Days 22 to 37) diets in each study contained 55 ppm bacitracin methylene disalicylate. The finisher diet (Days 38 to 42) in each study was unmedicated. Birds were inoculated via their feed on Day 22 (Study 1) or Day 15 (Study 2) with a mixed inoculum of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Four birds per pen (two male and two female) were randomly selected in each study for coccidial lesion scores on Day 6 postinoculation. These studies demonstrated that the use of 1 ppm diclazuril in shuttle programs was highly efficacious against a mixed inoculum of Eimeria spp. in comparison with nicarbazin, narasin + nicarbazin, and zoalene in starter diets and salinomycin, monensin, and lasalocid in grower diets.

Comparative testing of anticoccidials in broiler chickens: the role of coccidial lesion scores

The relationship between oocyst dose and lesion score was evaluated in trials involving five field isolates each of Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Each trial included an uninfected, unmedicated treatment, and at least three treatments of unmedicated birds given different doses of oocysts from a single isolate. In four trials each with E. acervulina and E. tenella, and all five trials with E. maxima, infected, salinomycin-medicated (60 ppm) treatments were included. Each treatment consisted of five cages with eight male broiler birds per cage using a randomized complete block design. The relationship between oocyst dose and lesion score was examined within each coccidial species using the linear model: Y = beta0 + beta1(log(n) oocyst dose + 1). The results demonstrated that in unmedicated birds, low oocyst doses caused mean lesion scores up to 2.0, but the numbers required to cause higher mean scores were many times greater. Second, the estimated oocyst dose in salinomycin-medicated birds for any given mean lesion score was substantially more than the corresponding estimate for unmedicated birds. These results indicated that there could be wide differences in levels of oocyst dose between unmedicated and medicated birds that lesion scores failed to measure. If lesion scores are used in trials comparing anticoccidial drugs, an alternative design may be to include three infected, unmedicated treatments each given a different level of inoculum (e.g., low, medium, and high). Medicated treatments, given the highest oocyst dose only, would then be compared to each of the infected, unmedicated treatments.

Effect of semduramicin, salinomycin, and monensin on performance, shank pigmentation, and coccidial lesions in broiler chickens in floor pens

The effects of 25 ppm semduramicin, 66 ppm salinomycin, 110 ppm monensin, and unmedicated treatments on performance, shank pigmentation, and coccidial lesion scores in broiler chickens were evaluated in two floorpen trials in the United States. On day 24 of each test, birds in each treatment were inoculated via the feed with a mixture of recent field isolates of Eimeria spp. at a dose rate calculated to provide 2 x 10(5) E. acervulina, 3 x 10(4) E. maxima, and 2 x 10(4) E. tenella sporulated oocysts per bird. Weight gain and feed conversion were significantly (P < or = 0.05) improved in the semduramicin-treated broilers in comparison with the monensin-treated and unmedicated broilers. These performance variables for the salinomycin-treated birds were intermediate between the semduramicin- and monensin-treated birds. Shank pigmentation scores were significantly (P < or = 0.05) improved in the three anticoccidial treatments compared with unmedicated birds, with the highest scores (P < or = 0.05) occurring in the semduramicin-treated broilers. Semduramicin was more efficacious (P < or = 0.05) than salinomycin in controlling upper intestinal lesions and more efficacious than monensin in controlling mid-intestinal lesions. All three drugs were comparable in controlling lesions in the ceca.

Efficacy of semduramicin and salinomycin against Eimeria maxima in a laboratory test using two levels of oocyst inocula

The anticoccidial efficacies of semduramicin and salinomycin against five field isolates of Eimeria maxima in broiler chickens were compared in five trials. Uninfected, unmedicated; infected, unmedicated; infected, 25 ppm semduramicin; and infected, 66 ppm salinomycin treatments were assigned to battery cages using a randomized, complete block design. Two levels of inocula, 10(3) and 10(4) oocysts per bird, were used in each trial in the infected treatments, creating a total of seven treatments per trial. Each treatment consisted of five replicate cages of eight broiler cockerels each. Medications were given in the feed continuously for 7 d beginning 24 h before inoculation. Response variables measured included bird weight gain by pen, feed consumption, feed conversion, plasma carotenoid concentrations, and coccidial lesion score. By using two levels of inocula it was demonstrated that the efficacy of each anticoccidial was equal to or greater than 90% in controlling these E. maxima isolates. It was also demonstrated that 25 ppm semduramicin was more efficacious than 66 ppm salinomycin based on improvements in weight gain, feed conversion, plasma carotenoid concentrations, and coccidial lesion control.

Anticoccidial efficacy of semduramicin. 2. Evaluation against field isolates including comparisons with salinomycin, maduramicin, and monensin in battery tests

The efficacy of semduramicin (AVIAX), a novel polyether ionophore, was profiled in a series of 57 battery tests conducted in the United States and the United Kingdom. The studies employed mixed and monospecific infections of Eimeria acervulina, Eimeria mivati/Eimeria mitis, Eimeria brunetti, Eimeria maxima, Eimeria necatrix, and Eimeria tenella derived from North American and European field isolates. Ten-day-old broiler cockerels in pens of 8 to 10 birds were continuously medicated in feed beginning 24 h before challenge in tests of 6 to 8 days' duration. At the use level of 25 ppm, semduramicin effectively controlled mortality, lesions, and weight gain depression that occurred in unmedicated, infected controls for all species. In comparison with 60 ppm salinomycin, semduramicin significantly (P < .05) improved weight gain against E. brunetti and E. tenella, lesion control against E. brunetti and E. maxima, and the control of coccidiosis mortality against E. tenella. Salinomycin was superior (P < .05) to all treatments in maintenance of weight gain and control of lesions for E. acervulina. Maduramicin at 5 ppm was inferior (P < .05) to semduramicin in control of E. acervulina and E. maxima lesions, but was superior (P < .05) to all treatments in maintenance of weight gain and control of lesions in E. tenella infections. The data indicate that semduramicin at 25 ppm is well tolerated in broilers and possesses broad spectrum anticoccidial activity.

Anticoccidial efficacy of semduramicin. 1. Evaluation against field isolates by dose titration in battery tests

Semduramicin (AVIAX), a novel polyether ionophore, was titrated in a series of five battery tests at 20, 25, and 30 ppm in feed to determine the optimum level for use. Twelve-day-old broiler chicks were medicated for 48 h prior to inoculation in each 9-day test. The inocula included monospecific field isolates of Eimeria tenella, Eimeria brunetti, Eimeria necatrix, and Eimeria maxima, and a mixture of these species with Eimeria acervulina and Eimeria mitis. The numbers of oocysts inoculated were selected after titration of each species and the mixture of species. All three concentrations of semduramicin significantly (P < .05) reduced coccidiosis mortality and lesion scores and achieved lower feed:gain ratios and greater weight gains than the infected, unmediated treatments. A concentration of 25 ppm semduramicin was determined to be optimal based on improved lesion control compared with 20 ppm and improved weight gain compared with 30 ppm.

"Spencer splint" for metacarpalphalangeal joint sprains

Images

Efficacy of semduramicin and salinomycin against different stages of Eimeria tenella and E. acervulina in the chicken

The efficacy of a new ionophore, semduramicin, was compared with salinomycin in a series of in ovo and in vivo trials. Semduramicin was more efficacious than salinomycin against Eimeria tenella sporozoites as judged by oocyst production in embryonated eggs. When the two drugs were given in ovo at 93 h post inoculation (PI), both drugs exerted some effect against late schizogonous stages of E. tenella. In three battery studies, semduramicin (25 ppm) and salinomycin (60 and 66 ppm) were tested against E. tenella and E. acervulina. Medicated feed was withdrawn at 24-h intervals PI to study the stage of action of the anticoccidials. In E. tenella infected chickens, both anticoccidials exerted their maximum effect on weight gain and feed:gain ratio through the first 72 h PI. Semduramicin was more effective than salinomycin in controlling E. tenella lesions and coccidiosis mortality. With E. acervulina, both drugs acted similarly on early life cycle stages and no improvement in performance was recorded when medicated feed was given for longer than 72 h. Semduramicin was more effective than salinomycin in controlling E. acervulina lesions.

Effects of different levels of oocyst inocula of Eimeria acervulina, E. tenella, and E. maxima on plasma constituents, packed cell volume, lesion scores, and performance in chickens

The effects of different levels of oocyst inocula of Eimeria acervulina, E. tenella, or E. maxima on plasma carotenoids, total plasma lipids, total plasma proteins, packed cell volume (PCV), bird performance, and coccidial lesion scores were determined in male Hubbard chickens. Each test consisted of an uninfected treatment and either four levels (E. tenella and E. maxima) or five levels (E. acervulina) of inocula. Carotenoids and lipids were significantly (P < or = 0.05) depressed by E. acervulina starting at 10(2) oocysts per bird, whereas 10(4) and higher inoculum levels significantly depressed plasma protein. Carotenoids and lipids were significantly depressed by E. tenella beginning at 10(4) oocysts per bird, whereas 10(2) oocysts per bird and greater levels significantly depressed plasma protein. E. maxima significantly depressed carotenoids and lipids beginning at 6.7 x 10(2) oocysts per bird and plasma protein at 6.7 x 10(4) oocysts per bird. PCV was depressed by E. acervulina and E. tenella starting at 10(4) oocysts per bird but was not affected by E. maxima. Weight gain was significantly depressed by E. acervulina beginning at 10(5) oocysts per bird, by E. tenella at 10(4) oocysts per bird, and by E. maxima at 6.7 x 10(4) oocysts per bird. Coefficients of determination (R2) were highest for carotenoids (0.96-0.99), followed by lipids (0.93-0.96), weight gain (0.89-0.91), feed:weight gain ratio (0.89-0.91), and protein and PCV (0.65-0.92). Results demonstrated that plasma carotenoids and lipids were excellent response variables for measuring the effects on broiler chickens of each of the Eimeria spp. tested.

Prophylactic medication with pyrantel to prevent liver condemnation in pigs naturally exposed to Ascaris infections

The use of pyrantel tartrate (106 mg/kg of feed) as a continuous feed medication was evaluated in 848 finishing hogs for efficacy in preventing Ascaris suum infections, and in reducing liver fibrosis and liver condemnation at slaughter, associated with A suum infections. Liver condemnations due to Ascaris damage were reduced 100% in all pigs given pyrantel, when compared with condemnation in non-medicated controls. None of the livers from any of the medicated animals was condemned, whereas livers from 101 (21%) of 479 nonmedicated pigs were condemned due to extensive hepatic scarring. Pyrantel medication administered for 62, 45, or 28 to 31 days resulted in reductions of total number of livers lesions at slaughter by 93.4%, 80.5%, and 68.6%, respectively. In nearly all cases, hepatic lesions remaining at slaughter of pigs given pyrantel in the feed were less distinct than were lesions found on livers from nonmedicated pigs.

The distribution of nematode eggs when using a dilution-egg-count procedure

By combining a number of well-known but scattered results, a theoretical model has been constructed to explain the observed quadratic increase in sample variance of egg counts over sample mean with increasing egg concentration. Our contention is that the over-dispersion arises because of inherent variation in volumetric deliveries of faecal suspension onto the counting slide. Even though the observed variation of volumetric deliveries appears to be small, we have shown that it is adequate to cause a considerable increase in egg count variance over mean at not unreasonably high concentrations.