Enhancing tuberculosis case finding in Tanzania: implementation of a quality improvement initiative.

Tuberculosis (TB) is one of the major causes of morbidity and mortality in Tanzania. A quality improvement (QI) initiative was implemented by the National Tuberculosis Programme with support from The Global Fund to enhance TB case finding. The initiative involved identifying gaps in the quality of services, introducing tools, building capacity of health workers, and strengthening laboratory and referral services. The initiative was piloted at sub-national level and subsequently scaled-up nationally. Overall, 1280 health workers were trained, leading to an 81% cumulative increase in notified TB cases in the pilot region and 4000 additional TB cases notified nationally. The QI initiative could serve as a model for the improvement of TB case notification in other settings.

La tuberculose (TB) est une des causes majeures de morbidité et de mortalité en Tanzanie. Une initiative d'amélioration de la qualité (QI) en trois points a été mise en œuvre par le Programme National Tuberculose avec un soutien du Fonds Mondial pour améliorer la détection des cas de TB. L'initiative a impliqué l'identification des failles de qualité des services de TB, l'introduction d'outils, le renforcement des capacités du personnel de santé, le renforcement du laboratoire TB et des services de référence. L'initiative a été pilotée au niveau sous national et ensuite étendue au niveau national : 1280 personnels de santé ont été formés, la coordination de la QI a été renforcée et ceci a contribué à 81% de l'augmentation cumulée des cas de TB notifiés dans la région pilote et à la notification de 4000 cas de TB supplémentaires au niveau national. L'initiative QI pourrait servir de modèle pour améliorer la notification des cas de TB dans d'autres contextes.

La tuberculosis (TB) es una de las principales causas de morbilidad y mortalidad en Tanzanía. El Programa Nacional contra la Tuberculosis introdujo, con el apoyo del Fondo Mundial, una iniciativa triple de mejoramiento de la calidad (QI) encaminada a reforzar la búsqueda de casos de TB. La iniciativa comportaba el reconocimiento de las deficiencias en la calidad de los servicios de TB, la introducción de instrumentos, el fortalecimiento de la capacidad de los trabajadores de salud y el refuerzo de los laboratorios de TB y los servicios de remisiones. Después de un ensayo piloto a escala subnacional, se amplió la iniciativa a todo el país. Se capacitaron 1280 trabajadores de salud y se reforzó la coordinación de la QI, con lo cual se propició un aumento acumulado de 81% de los casos de TB notificados en la región piloto y la notificación de 4000 casos de TB adicionales a escala nacional. La iniciativa de QI podría servir como modelo para mejorar la notificación de casos de TB en otros entornos.

Molecular monitoring of resistant dhfr and dhps allelic haplotypes in Morogoro and Mvomero districts in south eastern Tanzania.

BACKGROUND: Resistance to the antimalarial drug sulfadoxine-pyrimethamine (SP) emerged in Plasmodium falciparum from Asia in the 1960s and subsequently spread to Africa. In Tanzania, SP use as a national policy began in 1983 as a second line to chloroquine (CQ) for the treatment of uncomplicated malaria, until August 2001 when it was approved to replace CQ as a national first line. OBJECTIVE: The present study assesses the frequency of resistant dhfr and dhps alleles in Morogoro-Mvomero district in south eastern Tanzania and contrast their rate of change during 17 years of SP second line use against five years of SP first line use. METHODOLOGY: Cross sectional surveys of asymptomatic infections were carried out at the end of rainy season during July-September of 2000, when SP was the national second line (CQ was the first line) and 2006 when SP was the national first line antimalarial treatment. Genetic analysis of SP resistance genes was carried out on 1,044 asymptomatic infections and the effect of the two policies on SP evolution compared. RESULTS: The frequency of the most resistant allele, the double dhps-triple dhfr mutant genotype, increased by only 1% during 17 years of SP second line use, but there was a dramatic increase by 45% during five years of SP first line use. CONCLUSION: We conclude that National policy change from second line to first line SP, brought about an immediate shift in treatment practice and this in turn had a highly significant impact on drug pressure. The use of SP in specific programs only such as intermittent preventive treatment of infants (IPTi) and intermittent preventive treatment of pregnant women (IPTp) will most likely reduce substantially SP selection pressure and the SP resistance alleles alike.

Long-term impacts of poaching on relatedness, stress physiology, and reproductive output of adult female african elephants.

Widespread poaching prior to the 1989 ivory ban greatly altered the demographic structure of matrilineal African elephant (Loxodonta africana) family groups in many populations by decreasing the number of old, adult females. We assessed the long-term impacts of poaching by investigating genetic, physiological, and reproductive correlates of a disturbed social structure resulting from heavy poaching of an African elephant population in Mikumi National Park, Tanzania, prior to 1989. We examined fecal glucocorticoid levels and reproductive output among 218 adult female elephants from 109 groups differing in size, age structure, and average genetic relatedness over 25 months from 2003 to 2005. The distribution in group size has changed little since 1989, but the number of families with tusked old matriarchs has increased by 14.2%. Females from groups that lacked an old matriarch, first-order adult relatives, and strong social bonds had significantly higher fecal glucocorticoid values than those from groups with these features (all females R(2)= 0.31; females in multiadult groups R(2)= 0.46). Females that frequented isolated areas with historically high poaching risk had higher fecal glucocorticoid values than those in low poaching risk areas. Females with weak bonds and low group relatedness had significantly lower reproductive output (R(2)[U]=0.21). Females from disrupted groups, defined as having observed average group relatedness 1 SD below the expected mean for a simulated unpoached family, had significantly lower reproductive output than females from intact groups, despite many being in their reproductive prime. These results suggest that long-term negative impacts from poaching of old, related matriarchs have persisted among adult female elephants 1.5 decades after the 1989 ivory ban was implemented.

Patient's dissatisfaction with the public and private laboratory services in conducting HIV related testing in Tanzania.

BACKGROUND: Patient's satisfaction with both private and public laboratory services is important for the improvement of the health care delivery in any country. METHODS: A cross-sectional survey was conducted in 24 randomly selected health facilities with laboratories that are conducting HIV related testing, in Mainland Tanzania. The study assessed patient's satisfaction with the laboratory services where by a total of 295 patients were interviewed. RESULTS: Of data analyzed for a varying totals from 224 to 294 patients, the percentage of dissatisfaction with both public and private laboratory services, ranged from 4.3% to 34.8%, with most of variables being more than 15%. Patients who sought private laboratory services were less dissatisfied with the cleanness (3/72, 4.2%) and the privacy (10/72, 13.9%) than those sought public laboratory service for the same services of cleanness (41/222, 18.5%) and privacy (61/222, 27.5%), and proportional differences were statistically significant (X2 = 8.7, p = 0.003 and X2 = 5.5, p = 0.01, respectively). Patients with higher education were more likely to be dissatisfied with privacy (OR = 1.8, 95% CI: 1.1-3.1) and waiting time (OR = 2.5, 95% CI: 1.5 - 4.2) in both private and public facilities. Patients with secondary education were more likely to be dissatisfied with the waiting time (OR = 5.2; 95%CI: 2.2-12.2) and result notification (OR = 5.1 95%CI (2.2-12.2) than those with lower education. CONCLUSION: About 15.0% to 34.8% of patients were not satisfied with waiting time, privacy, results notification cleanness and timely instructions. Patients visited private facilities were less dissatisfied with cleanness and privacy of laboratory services than those visited public facilities. Patients with higher education were more likely to be dissatisfied with privacy and waiting time in both private and public facilities.

Dissatisfaction with the laboratory services in conducting HIV related testing among public and private medical personnel in Tanzania.

BACKGROUND: A comprehensive care and treatment program requires a well functioning laboratory services. We assessed satisfaction of medical personnel to the laboratory services to guide process of quality improvement of the services. METHODOLOGY: A cross-sectional survey in 24 randomly selected health facilities in Mainland Tanzania was conducted to assess the satisfaction of the medical personnel with the laboratory services. RESULTS: Of 235 medical personnel interviewed, 196 were valid for analysis and about one quarter were dissatisfied with the laboratory services. Personnel dissatisfied with the services were 38.3% in timely test result, 24.5% in correct and accurate results and 22.4% in clear complete results. The personnel in public laboratories were more dissatisfied with timely test results (OR = 3.6, 95% CI 1.8, 7.3), correct results (OR = 4.1, 95% CI 1.6, 10.8) and clear complete results (OR = 5.0 95% CI 1.6, 15.2). Personnel dissatisfied with the services in 15 laboratories sending specimens to referral laboratories, varied from 13% in availability of equipment to 57% in timely results feedback from the referral laboratories. Personnel dissatisfied with the services in 14 referral laboratories, varied from 28.6% in properly identified specimen to 42.9% in clear, accurate test request and communication. CONCLUSION: About one quarter of medical personnel in sending or receiving laboratories were dissatisfied with the services. Comparing the personnel in public and private, the personnel in public laboratories were 4 times more dissatisfied with the timely test and correct results; and 5 times more dissatisfied with clear and complete test results.

The quality of sputum smear microscopy diagnosis of pulmonary tuberculosis in Dar es Salaam, Tanzania.

This study was carried out to determine the rate of agreement or disagreement of microscopy reading and culture positivity rate among smear positixe and negative specimens between peripheral tuberculosis diagnostic centres (PDCs) and Central Reference luberculosis laboratory (CTRL). In this study 13 PDCs in Dar es Salaam, Tanzania were involved. Lot Quality Assurance Sampling (LQAS) method was used to collect 222 sputum smear slides. A total of 190 morning sputum specimens with corresponding slides were selected for culture. First readings were done by technicians at PDCs and thereafter selected slides and specimens were sent to CTRL for re-examination and culture. Culture results were used as a gold standard. Of 222 slides selected, 214 were suitable for re-examination. Percentage of agreement of smear reading between PDCs and CTRL was 42.9% and 100% for positive and negative slides, respectively. Measure of agreement (Kappa statistic) was 0.5, indicating moderate agreement. Of 190 samples cultured, percentage of agreement between smear reading from PDCs and CTRL was 37% and 88.9% for smear positive and negative slides, respectively. Kappa statistic was 0.3 indicating poor-fair agreements. Comparison of smear reading from PDCs with culture showed sensitivity of 36.9% and specificity of 88.9%. Comparison of smear readings from CTRL with culture results showed sensitivity of 95.6% and specificity of 98.6%. In conclusion there was inadequate performance in diagnosis of TB using smear microscopy among peripheral diagnostic centres in Dar es Salaam. This calls for immediate and rigorous measures to improve the quality of smear microscopy. It is therefore important to strengthen the capacity of laboratory personnel in smear microscopy techniques through supportive supervision and training.

Quality of HIV laboratory testing in Tanzania: a situation analysis.

Tanzania is scaling up prevention, treatment, care and support of individuals affected with HIV. There is therefore a need for high quality and reliable HIV infection testing and AIDS staging. The objective of this study was to assess laboratories capacities of services in terms of HIV testing and quality control. A baseline survey was conducted from December 2004 to February 2005 in 12 laboratories which were conveniently selected to represent all the zones of Tanzania. The questionnaires comprised of questions on laboratory particulars, internal and external quality control for HIV testing and quality control of reagents. Source and level of customer satisfaction of HIV test kits supply was established. Of 12 laboratories, nine used rapid tests for screening and two used rapid tests for diagnosis. In the 12 laboratories, four used double ELISA and five used single ELISA and three did not use ELISA. Confirmatory tests observed were Western Blot in three laboratories, DNA PCR in two laboratories, CD4 counting in seven laboratories, and viral load in two laboratories. Although all laboratories conducted quality control (QC) of the HIV kits, only two laboratories had Standard Operating Procedures (SOPs). Internal and external quality control (EQC) was done at varied proportions with the highest frequency of 55.6% (5/9) for internal quality control (IQC) for rapid tests and EQC for ELISA, and the lowest frequency of 14.3% (1/ 7) for IQC for CD4 counting. None of the nine laboratories which conducted QC for reagents used for rapid tests and none of the five which performed IQC and EQC had SOPs. HIV kits were mainly procured by the Medical Store Department and most of laboratories were not satisfied with the delay in procurement procedures. Most of the laboratories used rapid tests only, while some used both rapid tests and ELISA method for HIV testing. In conclusion, the survey revealed inadequacy in Good Laboratory Practice and poor laboratory quality control process for HIV testing reagents, internal and external quality control.

Quality of HIV laboratory testing in Tanzania: a situation analysis

Tanzania is scaling up prevention; treatment; care and support of individuals affected with HIV. There is therefore a need for high quality and reliable HIV infection testing and AIDS staging. The objective of this study was to assess laboratories capacities of services in terms of HIV testing and quality control. A baseline survey was conducted from December 2004 to February 2005 in 12 laboratories which were conveniently selected to represent all the zones of Tanzania. The questionnaires comprised of questions on laboratory particulars; internal and external quality control for HIV testing and quality control of reagents. Source and level of customer satisfaction of HIV test kits supply was established. Of 12 laboratories; nine used rapid tests for screening and two used rapid tests for diagnosis. In the 12 laboratories; four used double ELISA and five used single ELISA and three did not use ELISA. Confirmatory tests observed were Western Blot in three laboratories; DNA PCR in two laboratories; CD4 counting in seven laboratories; and viral load in two laboratories. Although all laboratories conducted quality control (QC) of the HIV kits; only two laboratories had Standard Operating Procedures (SOPs). Internal and external quality control (EQC) was done at varied proportions with the highest frequency of 55.6(5/9) for tnternal quality control (IQC) for rapid tests and EQC for ELISA; and the lowest frequency of 14.3(1/ 7) for IQC for CD4 counting. None of the nine laboratories which conducted QC for reagents used for rapid tests and none of the five which performed IQC and EQC had SOPs. HIV kits were mainly procured by the Medical Store Department and most of laboratories were not satisfied with the delay in procurement procedures. Most of the laboratories used rapid tests only; while some used both rapid tests and ELISA method for HIV testing. In conclusion; the survey revealed inadequacy in Good Laboratory Practice and poor laboratory quality control process for HIV testing reagents; internal and external quality control

Participatory involvement of farming communities and public sectors in determining malaria control strategies in Mvomero District, Tanzania.

Addressing the malaria-agriculture linkages requires a broad inter-disciplinary and integrated approach that involves farming communities and key public sectors. In this paper, we report results of participatory involvement of farming communities in determining malaria control strategies in Mvomero District, Tanzania. A seminar involving local government leaders, health and agricultural officials comprising of a total of 27 participants was held. Public meetings in villages of Komtonga, Mbogo, Mkindo, Dihombo and Luhindo followed this. Findings from a research on the impact of agricultural practices on malaria burden in the district were shared with local communities, public sector officials and other key stakeholders as a basis for a participatory discussion. The community and key stakeholders had an opportunity to critically examine the linkages between agricultural practices and malaria in their villages and to identify problems and propose practical solutions. Several factors were identified as bottlenecks in the implementation of malaria control in the area. Lack of community participation and decision making in malaria interventions was expressed as among the major constraints. This denied the community the opportunities of determining their health priorities and accessing knowledge needed to effectively implement malaria interventions. In conclusion, this paper emphasizes the importance of participatory approach that involves community and other key stakeholders in malaria control using an ecosystem approach. An interdisciplinary and integrated approach is needed to involve farmers and more than one sector in malaria control effort.

Plasma bioactive LH and testosterone profiles in male New Zealand rabbits experimentally infected with Schistosoma mansoni.

The effects of Schistosoma mansoni (S. mansoni) infection on plasma levels of bioactive luteinising hormone (LH) and testosterone in the New Zealand rabbit model were studied. S. mansoni infection significantly decreased the pulse frequency (P < 0.05), amplitude (P < 0.05), area under LH curve (P < 0.05) and mean plasma LH concentrations (P < 0.05) on days 42 and 70 post-infection, as compared to values for day 14 pre-infection. Areas under the response curves for plasma testosterone levels decreased significantly (P < 0.05) on days 42 and 70 post-infection in infected animals compared to day 14 pre-infection. In the praziquantel-treated group, the levels of LH and testosterone remained unchanged throughout the experimental period. The pulsatile secretion of LH was completely inhibited in S. mansoni-infected animals 70 days post-infection. These results suggest that the effects on reproductive gonadal hormones caused by S. mansoni in the rabbit model may partly be induced by alteration in pituitary synthesis or release of LH.

Application of PCR and DNA probes in the characterisation of trypanosomes in the blood of cattle in farms in Morogoro, Tanzania.

Polymerase chain reaction (PCR) and deoxyribonucleic acid (DNA) probes were used to characterise trypanosomes from cattle in Morogoro region of Tanzania. Blood samples collected from 390 beef and dairy cattle in selected farms in Morogoro region were examined for presence of trypanosomes using the buffy coat technique (BCT) and blood smears (BSs). Fifty-two animals were found infected: 40 with Trypanosoma congolense, 10 with T. vivax and two with both T. congolense and T. vivax. DNA extracted from all the parasitologically positive and 62 randomly selected parasitologically negative samples were subjected to PCR amplification using primers specific for different trypanosome species. Using a set of seven specific-pairs of primers on the parasitologically positive samples, we detected only T. congolense, either the Savannah- or the Kilifi-type, as single or mixed infections. With the PCR, trypanosome DNA could be detected in 27 (43%) out of 62 samples that were parasitologically negative. DNA hybridisation using probes specific for Savannah- or Kilifi-types T. congolense, or T. vivax, confirmed the presence of these parasites in cattle kept on some farms in Morogoro region of Tanzania. From these studies, it is clear that there is a need to undertake molecular epidemiological studies to determine the distribution of trypanosome species and subspecies, and to assess the economic impact of these parasites in the productivity of livestock in Tanzania. In particular, it would be desirable to verify the assumed association between the different presentations of trypanosomosis on one hand and genotypes of T. congolense on the other.

Effect of experimental infection with Trypanosoma congolense and scrotal insulation on Leydig cell steroidogenesis in the ram.

Testicular steroid content and Leydig cell steroidogenesis in vitro were investigated in rams on Days 28 and 58 after Trypanosoma congolense infection and were compared with those of rams in which testicular temperature had been raised artificially by insulation of the scrotum for 58 d. Testicular testosterone content increased significantly on Day 28 after infection but was lower than that of controls on Day 58 while it increased in scrotal-insulated rams compared with that of controls by Day 58. Testicular progesterone was undetectable in the control and trypanosome-infected groups throughout the experiment, but it increased in the insulated rams by day 58. Basal (unstimulated) Leydig cell testosterone production in the infected rams was similar to that of control rams on Day 28 but was significantly lower on Day 58. Stimulation of Leydig cell testosterone production with hCG or 22R-hydroxycholesterol (22ROHC) significantly reduced in infected rams at both 28 and 58 d after infection as well as in scrotal-insulated rams on Day 58. It is concluded that the increase in testicular testosterone content in the infected and scrotal-insulated rams on Days 28 and 58, respectively, was induced by elevation of testicular temperature by trypanosome infection, perhaps through an effect on testicular blood flow. Reduced testosterone production by Leydig cells from infected and scrotal-insulated rams in response to hCG and 22ROHC suggests that trypanosome-induced pyrexia might be involved in reducing Leydig cell steroidogenesis and subsequent plasma testosterone levels, possibly by affecting enzymes involved in steroid biosynthesis.

Effects of castration on luteinizing hormone secretion and response to gonadotrophin-releasing hormone in sheep infected with Trypanosoma congolense.

The effects of trypanosomiasis on the endocrine function of the hypothalamo-pituitary-gonadal axis were investigated before and after castration of Scottish Blackface rams infected with Trypanosoma congolense and uninfected controls. Blood samples were collected at 15-min intervals for 6 h before and at 10, 20, 40, 60, 80, 100 and 120 min after injection of synthetic gonadotrophin-releasing hormone (GnRH, 20 micrograms iv) 2 days before infection and 26 and 54 days after infection, with castration being performed 28 days after infection. Mean luteinizing hormone (LH) pulse amplitude was higher (3.3 +/- 0.2 vs 2.6 +/- 0.3 ng/ml) and mean plasma testosterone concentration was lower (4.1 +/- 0.6 vs 7.6 +/- 1.2 nmol/l) in infected vs control rams 26 days after infection (p < 0.05). Mean plasma LH concentration and pulse amplitude increased in both groups after castration but both were significantly lower in infected compared to control rams (6.6 +/- 1.5 and 13.0 +/- 2.2 ng/ml, p < 0.01; 7.7 +/- 0.9 and 11.6 +/- 0.9 ng/ml, p < 0.001), respectively. However, LH responses to exogenous GnRH were similar in infected and control rams at each stage of the experiment, suggesting that the smaller increase in plasma LH after castration in infected rams was not caused by reduced responsiveness of the pituitary to GnRH but by alterations in GnRH secretion by the hypothalamus or its transport to the adenohypophysis. These results also demonstrate that impairment of testosterone secretion within 4 weeks of T. congolense infection in sheep may be due to testicular rather than pituitary effects.

Effects of Trypanosoma congolense on pituitary and adrenocortical function in sheep: changes in the adrenal gland and cortisol secretion.

The effect of trypanosomiasis on adrenal function was studied in 10 pubertal Scottish blackface rams infected with Trypanosoma congolense and nine uninfected controls. Plasma cortisol concentration was measured by radioimmunoassay in samples obtained twice a week for three weeks before infection and three times a week for 79 days after infection. There was a significant (P < 0.001) increase in cortisol concentration in all the infected rams after the onset of parasitaemia nine to 16 days after infection. This was followed by a transient non-significant decrease in cortisol levels between 19 and 41 days and a variable and parasitaemia-dependent increase in cortisol levels between 44 and 79 days after infection. Marked hypertrophy of the zona fasciculata-reticularis, infiltration of mononuclear cells into the cortical and medullary zones, hyperaemia and focal coagulative necrosis were evident in the adrenal glands of infected rams killed at the end of the study. Trypanosome infection induced a low grade persistent pyrexia, marked anaemia, reduced growth rates and general loss of body condition. These results demonstrate that T congolense infection in sheep causes marked pathological changes in the adrenal cortex and changes in the secretion of cortisol.

Effects of Trypanosoma congolense on pituitary and adrenocortical function in sheep: responses to exogenous corticotrophin-releasing hormone.

To investigate whether the aberrations in adrenocortical and gonadal activity observed in trypanosomiasis may be induced by the refractoriness of the pituitary to hypothalamic liberins, the responses of the pituitary and adrenal glands and the testes to stimulation with ovine corticotrophin-releasing hormone (oCRH) were studied in rams 23 days (acute phase) and 65 days (chronic phase) after they were infected with Trypanosoma congolense. On both occasions a peak of plasma ACTH was observed within 20 minutes of the injection of CRH but the rate of increase in ACTH and the mean peak values in the infected rams were significantly lower (P < 0.001) on day 23 but higher (P < 0.05) on day 65 than in the uninfected control rams. Plasma cortisol concentration increased in all the rams after the injection of CRH. The rate of increase in plasma cortisol and the mean peak values were not significantly different between the control and infected rams on day 23 but were significantly (P < 0.001) higher in the infected rams on day 65. However, the post peak concentrations of ACTH declined more rapidly in the infected rams than in the controls on both days 23 and 65. The plasma concentration of luteinising hormone (LH) did not change after the injection of CRH, whereas the testosterone levels showed a delayed response and its concentration increased when plasma ACTH and cortisol concentrations declined in both groups. On day 23, there was a greater increase in testosterone in the infected than in the control rams.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of Trypanosoma congolense infection in rams on the pulsatile secretion of LH and testosterone and responses to injection of GnRH.

Changes in pulsatile secretion of LH and testosterone and responses to exogenous GnRH were assessed at different stages of Trypanosoma congolense infection in rams. Jugular blood samples were collected every 15 min for 6 h followed by immediate injection of GnRH (20 micrograms i.v.) and further sample collection after 10, 20, 40, 60, 80, 100 and 120 min. This sampling and injection regimen was performed 5 days before infection (day -5) and 23 and 52 days after infection. T. congolense infection increased (P < 0.05) the mean plasma LH concentration over 6 h on day 23 (3.2 +/- 0.2 ng ml-1) and decreased (P < 0.05) the mean LH concentration on day 52 (1.2 +/- 0.2 ng ml-1, P < 0.05) compared with day -5 values (2.0 +/- 0.2 ng ml-1). Trypanosome infection induced a rapid decline in plasma testosterone concentration from a mean of 7.5 +/- 1.4 nmol l-1 on day -5 over 6 h to 3.6 +/- 0.4 nmol l-1 (P < 0.05) on day 23 and 1.7 +/- 0.3 nmol l-1 (P < 0.001) on day 52. The observed decline in plasma LH concentration in infected rams was not associated with reduced sensitivity of the pituitary to GnRH or its ability to release LH, as the LH response to exogenous GnRH was not impaired throughout the period of infection. However, the testosterone response to GnRH-induced LH stimulation was depressed on both days 23 and 52 after infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Development of a sensitive enzyme immunoassay for LH determination in bovine plasma using the streptavidin-biotin technique.

Using the biotin-streptavidin amplification technique, highly sensitive specific second-antibody enzyme immunoassays for determining LH in bovine plasma with long (48 h) and short (4 h) incubation periods were developed. Biotin was linked to bLH by the N-hydroxysuccinimide method and the product (biotinyl-bLH) used to bridge between streptavidin-peroxidase and the immobilised bLH antibody in competitive tests. The assays were validated and their performance compared with a radioimmunoassay currently in use. The sensitivities of the long and short incubation enzyme immunoassays (8 pg and 15 pg/well, respectively) were superior to that of 5-day incubation radioimmunoassay (100 pg/tube). Plasma interference in both assays were acceptable and volumes of 5 to 40 microliters gave parallel standard curves and comparable LH levels, 10-20 microliters plasma was sufficient to measure LH baseline levels by the long incubation enzyme immunoassay. The mean recovery of added standard bLH to plasma samples containing different endogenous LH was greater than 90% (range 91.7-112) in both assays. The intra- and inter-assay variations of both assays were less than 10 and 17%, respectively. When both enzyme immunoassay and radioimmunoassay were used to measure LH in cyclic cows, the basal levels measured by enzyme immunoassay were lower than that measured by radioimmunoassay. Enzyme immunoassay offers an attractive alternative to the lengthy radioimmunoassay in current usage, with an added advantage of employing non-isotopic label.

Immunoaffinity chromatography and a biotin-streptavidin amplified enzymeimmunoassay for sensitive and specific estimation of estradiol-17 beta.

A sensitive test system has been developed for estimation of estradiol-17 beta (E2) in bovine plasma. Plasma extracts are first purified by a selective immunoaffinity chromatography (IAC) using an antibody raised against estradiol-6-carboxymethyloxime-bovine serum albumin and immobilized to Sepharose. The eluate was analysed by a competitive enzyme immunoassay (EIA) on microtitration plates. For the assay the wells of microtitration plates were coated with affinity purified sheep IgG (antirabbit IgG) that binds the hormone specific antibody raised in rabbits against estradiol-17-hemisuccinate-bovine serum albumin. E2 is estimated by displacement of biocytinyl-E2, that was produced by ligation of estradiol-17 beta, D-glucuronic acid and biocytin. Bound biocytinyl-E2 is detected after binding of streptavidin-peroxidase and colour production by the enzyme. A very high amplification was possible with this technique and the absolute detection limit amounted to approximately 120 fg/well at 94% relative binding. By combination of IAC and EIA the following levels of E2 were found in bovine plasma: male or female calves less than 2.7 pg/ml, cycling cow 0.5-7 pg/ml, cow during the last month of pregnancy 9-310 pg/ml, mature bull 5-30 pg/ml. However, up to 1110 pg E2/ml were found in plasma of a calf after treatment with an illicit hormone preparation used for growth promotion; after 21 days levels declined to 6 pg/ml which is hardly different from controls. In conclusion, the IAC/EIA can be used for sensitive estimation of estradiol-17 beta in plasma from all type of cattle and for control of improper use of E2 after commitment of a threshold level.

Effect of African trypanosomiasis on plasma cortisol and thyroxine concentration in goats.

Changes in plasma cortisol and thyroxine (T4) levels were measured weekly in female goats experimentally infected with Trypanosoma congolense. Values for plasma cortisol (range 10 to 25 nmol litre-1) and T4 (range 65 to 120 nmol litre-1) were within normal ranges in all goats before infection and in control animals throughout the 24 weeks of study. Cortisol/T4 ratios of 0.23 to 0.15 (or 1:4 to 1:7) were obtained. In the infected goats a significant increase in cortisol and decline in T4 were simultaneously observed within one week of the onset of parasitaemia and fever. A peak cortisol/T4 ratio of 2.0 (2:1) was obtained four weeks after infection when cortisol levels rose to 59.0 +/- 8.9 nmol litre-1 and T4 declined to 29.4 +/- 2.2 nmol litre-1. Thereafter the mean levels fluctuated but remained high (over 30 nmol litre-1) for cortisol and low (under 50 nmol litre-1) for T4 up to 18 weeks after infection. Both hormones tended to return to normal levels towards the end of the study. The changes in mean cortisol levels showed a significant inverse correlation with changes in T4 (r = -0.57, P less than 0.001, n = 26). It is suggested that in trypanosomiasis, hypothalamic stress causes increases in plasma cortisol levels and at the same time suppresses the activity of the thyroid gland.