Health laboratories in the Tanga region of Tanzania: the quality of diagnostic services for malaria and other communicable diseases.

Although critical for good case management and the monitoring of health interventions, the health-laboratory services in sub-Saharan Africa are grossly compromised by poor infrastructures and a lack of trained personnel, essential reagents and other supplies. The availability and quality of diagnostic services in 37 health laboratories in three districts of the Tanga region of Tanzania have recently been assessed. The results of the survey, which involved interviews with health workers, observations and a documentary review, revealed that malaria accounted for >50% of admissions and out-patient visits. Most (92%) of the laboratories were carrying out malaria diagnosis and 89% were measuring haemoglobin concentrations but only one (3%) was conducting culture and sensitivity tests, and those only on urine and pus samples. Only 14 (17%) of the 84 people found working in the visited laboratories were laboratory technologists with a diploma certificate or higher qualification. Sixteen (43%) of the study laboratories each had five or fewer types of equipment and only seven (19%) had more than 11 types each. Although 11 (30%) of the laboratories reported that they conducted internal quality control, none had standard operating procedures (SOP) on display or evidence of such quality assurance. Although malaria was the main health problem, diagnostic services for malaria and other diseases were inadequate and of poor quality because of the limited human resources, poor equipment and shortage of supplies. If the health services in Tanga are not to be overwhelmed by the progressively increasing burden of HIV/AIDS, malaria, tuberculosis and other emerging and re-emerging diseases, more funding and appropriate policies to improve the availability and quality of the area's diagnostic services will clearly be required.

Biological and haematological safety profile of oral amodiaquine and chloroquine in healthy volunteers with or without Plasmodium falciparum infection in northeast Tanzania.

Amodiaquine (AQ), an effective antimalarial drug for uncomplicated malaria, has been greatly restricted after cases of life-threatening agranulocytosis and hepatic toxicity during prophylactic use. We conducted a hospital based open-label randomised clinical trial in 40 indigenous semi-immune healthy adult male volunteers with and without malaria parasites. The objective was to collect data on biological and haematological safety, tolerability, and parasitological efficacy to serve as baseline in the evaluation of the effectiveness of AQ preventive intermittent treatment against malaria morbidity in infants. Volunteers were stratified according to parasitaemia status and randomly assigned 20 participants each arm to three days treatment with either AQ or chloroquine (CQ). The level of difference of selected haematological and hepatological values pre-and post-trial were marginal and within the normal limits. Clinical adverse effects mostly mild and transient were noticed in 33.3% CQ treated-aparasitaemic, 23.8% of CQ treated-parasitaemic, 28.6% ofAQ-treated parasitaemic and 14.3% of aparasitaemic receiving AQ. Amodiaquine attained 100% parasitological clearance rate versus 70% in CQ-treated volunteers. The findings indicate that there was no agranulocytosis or hepatic toxicity suggesting that AQ may pose no public health risk in its wide therapeutic dosage uses. Larger studies are needed to exclude rare adverse effects.

Biological and Haematological Safety Profile of Oral Amodiaquine and Chloroquine in Healthy Volunteers with or without Plasmodium falciparum Infection in Northeast Tanzania

Amodiaquine (AQ); an effective antimalarial drug for uncomplicated malaria; has been greatly restricted after cases of life-threatening agranulocytosis and hepatic toxicity during prophylactic use. We conducted a hospital based open-label randomised clinical trial in 40 indigenous semi-immune healthy adult male volunteers with and without malaria parasites. The objective was to collect data on biological and haematological safety; tolerability; and parasitological efficacy to serve as baseline in the evaluation of the effectiveness of AQ preventive intermittent treatment against malaria morbidity in infants. Volunteers were stratified according to parasitaemia status and randomly assigned 20 participants each arm to three days treatment with either AQ or chloroquine (CQ). The level of difference of selected haematological and hepatological values pre-and post-trial were marginal and within the normal limits. Clinical adverse effects mostly mild and transient were noticed in 33.3CQ treated-aparasitaemic; 23.8of CQ treated-parasitaemic; 28.6of AQ-treated parasitaemic and 14.3of aparasitaemic receiving AQ. Amodiaquine attained 100parasitological clearance rate versus 70in CQ-treated volunteers. The findings indicate that there was no agranulocytosis or hepatic toxicity suggesting that AQ may pose no public health risk in its wide therapeutic dosage uses. Larger studies are needed to exclude rare adverse effects

The roles of the pfcrt 76T and pfmdr1 86Y mutations, immunity and the initial level of parasitaemia, in predicting the outcome of chloroquine treatment in two areas with different transmission intensities.

The resistance of Plasmodium falciparum to chloroquine (CQ) is probably mediated by point mutations in two genes: pfcrt and pfmdr1. The aim of the present study was to investigate, in patients treated with CQ, the association between host factors, such as immunity and initial level of parasitaemia, and the ability to clear P. falciparum parasites carrying the key chloroquine-resistance (CQR) mutations, pfcrt 76T and pfmdr1 86Y. Identical CQ-efficacy trials were performed in 51 young children (aged <5 years) from Kibaha, in north-western Tanzania, and 44 patients (aged 3-57 years) from Darawish, in eastern Sudan. In both areas, all the CQ-treatment failures had infections with the 76T and 86Y alleles before treatment. Although the presence of these two alleles was significantly associated with treatment failure in Sudan (P=0.001), the corresponding association in Tanzania did not reach statistical significance (P=0.1). Of the 39 patients from Darawish and 44 from Kibaha who harboured parasites with the CQR mutations, 12 and 19, respectively, managed to clear their parasitaemias. The ability to clear CQR parasites was significantly associated with the initial level of parasitaemia (with P-values of 0.05 in Tanzania and 0.01 in Sudan) and with age-- the best surrogate for protective immunity in endemic areas (with P-values of 0.02 in Tanzania and 0.001 in Sudan). These results confirm previous observations that indicated that the 76T and 86Y alleles play a role in the mechanism of CQR, although other factors, such as level of parasitaemia when treated and age, are also important. The 76T and 86Y alleles could still be used as predictive markers for CQR, in non-immune individuals and low-transmission areas.

The use of nominal group technique in identifying community health priorities in Moshi rural district, northern Tanzania.

This article highlights issues pertaining to identification of community health priorities in a resource poor setting. Community involvement is discussed by drawing experience of involving lay people in identifying priorities in health care through the use of Nominal Group Technique. The identified health problems are compared using four selected village communities of Moshi district in Kilimanjaro region, Tanzania. We conducted this study to trace the experience and knowledge of lay people as a supplement to using 'health experts' in priority setting using malaria as a tracer condition. The patients/caregivers, women's group representatives, youth leaders, religious leaders and community leaders/elders constituted the principal subjects. Emphasis was on providing qualitative data, which are of vital consideration in multi-disciplinary oriented studies, and not on quantitative information from larger samples. We found a high level of agreement across groups, that malaria remains the leading health problem in Moshi rural district in Tanzania both in the highland and lowland areas. Our findings also indicate that 'non-medical' issues including lack of water, hunger and poverty heralded priority in the list implying that priorities should not only be focused on diseases, but should also include health services and social cultural issues. Indeed, methods which are easily understood and applied thus able to give results close to those provided by the burden of disease approaches should be adopted. It is the provision of ownership of the derived health priorities to partners including the community that enhances research utilization of the end results. In addition to disease-based methods, the Nominal Group Technique is being proposed as an important research tool for involving the non-experts in priority setting in Tanzania.

Efficacy of chloroquine, amodiaquine, sulphadoxine-pyrimethamine and combination therapy with artesunate in Mozambican children with non-complicated malaria.

This paper reports a two-phase study in Manhiça district, Mozambique: first we assessed the clinical efficacy and parasitological response of Plasmodium falciparum to chloroquine (CQ), sulphadoxine-pyrimethamine (SP) and amodiaquine (AQ), then we tested the safety and efficacy in the treatment of uncomplicated malaria, of three combinations: AQ + SP, artesunate (AR) + SP and AQ + AR. Based on the WHO (1996, WHO/MAL/96.1077) in vivo protocol, we conducted two open, randomized, clinical trials. Children aged 6-59 months with axillary body temperature > or = 37.5 degrees C and non-complicated malaria were randomly allocated to treatment groups and followed up for 21 days (first and second trial) and 28 days (first trial). The therapeutic efficacy of AQ (91.6%) was better than that of SP (82.7%) and CQ (47.1%). After 14 days, 69% of the strains were parasitologically resistant to CQ, 21.4% to SP and 26% to AQ. Co-administration of AQ + SP, AR + SP and AQ + AR was safe and had 100% clinical efficacy at 14-day follow-up. The combination therapies affected rapid fever clearance time and reduced the incidence of gametocytaemia during follow-up.

Efficacy of chloroquine, amodiaquine, sulphadoxine­pyrimethamine and combination therapy with artesunate in Mozambican children with non-complicated malaria

This paper reports a two-phase study in Manhiça district, Mozambique: first we assessed the clinical efficacy and parasitological response of Plasmodium falciparum to chloroquine (CQ), sulphadoxine-pyrimethamine (SP) and amodiaquine (AQ), then we tested the safety and efficacy in the treatment of uncomplicated malaria, of three combinations: AQ + SP, artesunate (AR) + SP and AQ + AR. Based on the WHO (1996, WHO/MAL/96.1077) in vivo protocol, we conducted two open, randomized, clinical trials. Children aged 6-59 months with axillary body temperature > or = 37.5 degrees C and non-complicated malaria were randomly allocated to treatment groups and followed up for 21 days (first and second trial) and 28 days (first trial). The therapeutic efficacy of AQ (91.6%) was better than that of SP (82.7%) and CQ (47.1%). After 14 days, 69% of the strains were parasitologically resistant to CQ, 21.4% to SP and 26% to AQ. Co-administration of AQ + SP, AR + SP and AQ + AR was safe and had 100% clinical efficacy at 14-day follow-up. The combination therapies affected rapid fever clearance time and reduced the incidence of gametocytaemia during follow-up.

Tissue levels, histologic changes and plasma pharmacokinetics of meta-Tetra (hydroxyphenyl) chlorin (mTHPC) in the cat.

The biodistribution and pharmacokinetics of meta-tetra(hydroxyphenyl)chlorin (mTHPC)(1) have been documented in humans, rats, dogs and rabbits. It has been demonstrated to be an effective photodynamic therapy agent for treatment of squamous cell carcinoma. Squamous cell carcinoma is a common feline neoplasm, causing significant morbidity and mortality in the feline population. The association between ultraviolet radiation exposure and occurrence of this neoplasm in the cat provides a useful model for the study of human cutaneous squamous cell carcinoma. In this study, we document the biodistribution, pharmacokinetics and toxicity of mTHPC in a group of normal cats. Four groups of cats were given the drug intravenously at dosages of 0, 0.15, 0.30 and 0.60 mg/kg. mTHPC levels were measured in plasma and tissues at 0, 24, 48, 72, 96 and 336 h after drug administration. Additionally, plasma samples were collected at 1 and 6 h post-injection and analysed. Biodistribution and pharmacokinetics of mTHPC in cats mirrors that in other animal species. There were no clinical or pathological changes associated with administration of the drug. The biodistribution and pharmacokinetics of mTHPC in cats mirrors that in other species studied. There were no clinical or pathological changes attributable to administration of the drug at the doses administered. mTHPC may be a useful photodynamic therapy drug in cats.

A reversed-phase high-performance liquid chromatography method for the determination of cotrimoxazole (trimethoprim/ sulphamethoxazole) in children treated for malaria.

A high-performance liquid chromatography (HPLC) method was developed for the simultaneous analysis of trimethoprim (TMP), sulphamethoxazole (SMX), and acetylsulphamethoxazole (AcSMX) in small amounts of blood. The method involved precipitation with 50 microL trichloracetic acid (1M) to 125 microL plasma or serum sample. 60 microL supernatant was added to 60 microL mobile phase, modified with 50microL 1 M sodium hydroxide/mL. The mobile phase consisted of 20% acetonitrile and 80% phosphate buffer adjusted to pH 6.15. Using 125 microL of the sample, limits of quantitation were 0.1 microg/mL for TMP, 1.0 microg/mL for SMX, and 1.0 microg/mL for AcSMX. The precision of the method was 2% to 11% over the range of concentrations tested, 0.5-30 microg/mL for TMP, 5-300 microg/mL for SMX, and 2.5-150 microg/mL for AcSMX, respectively. No interference with other commonly used drugs was observed. The method is rapid, simple, specific, and sensitive enough for pharmacokinetic studies. The small amount of blood required makes it suitable for pediatric patients. The method was used to analyze samples from Tanzanian children aged 6-59 months participating in a cotrimoxazole (TMP/SMX)/chloroquine randomized trial for the treatment of uncomplicated malaria. Venous blood samples from 68 children were collected 2 hours after the first dose of TMP/SMX (4 mg/kg TMP/20 mg/kg SMX at two divided doses for 5 days) and again at treatment day 4. Individual variations in plasma concentrations of TMP, SMX, and AcSMX were considerable. The mean and SEM plasma concentrations (g/mL) of TMP, SMX, and AcSMX 2 hours after the first treatment dose were 2.0 +/- 1.0 (range 0.5-6), 53 +/- 22 (range 24-146), and 13.5 +/- 12 (range 0-65), respectively. On the fourth day the attained plasma concentrations were not significantly different from samples collected after the first dose.

[Long-lasting neuropsychiatric side-effects following mefloquine prophylaxis. A case after six weeks of initiating and lasting six months]. / Langvarige neuropsykiatriske bivirkninger efter meflochinprofylakse. Et seks måneder varende tilfaelde opstået efter seks ugers brug.

Neuropsychiatric side-effects from mefloquine are well known. When used for prophylaxis, the side-effects have been claimed to be relatively rare, mild and transient, most often arising within two to three weeks, and in patients with a previous history of neuropsychiatric disorders. We here describe a case of severe neuropsychiatric side-effects arising six weeks after initiating mefloquine prophylaxis, requiring repeated hospitalization, and not resolving completely after six months, in a previously healthy 30 year-old female.

Polymorphisms in the dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) genes of Plasmodium falciparum and in vivo resistance to sulphadoxine/pyrimethamine in isolates from Tanzania.

The efficacy of sulphadoxine/pyrimethamine (S/P) in treatment of uncomplicated falciparum malaria in Africa is increasingly compromised by development of resistance. The occurrence of mutations associated with the active site sequence in the Plasmodium falciparum genes coding for dihydrofolate reductase (DHFR) and dihydropteroate synthetase (DHPS) is associated with in vitro resistance to pyrimethamine and sulphadoxine. This study investigates the occurrence of these mutations in infected blood samples taken from Tanzanian children before treatment with S/P and their relationship to parasite breakthrough by day 7. The results show that alleles of DHPS (436-alanine, 437-alanine and 540-lysine) were significantly reduced in prevalence on day 7 after S/P treatment. In this area, a DHPS with 436-serine, 437-glycine and 540-glutamate appears to play a major role in resistance to S/P in vivo. Evidence for the influence of mutations in the DHFR gene in this investigation is not clear, probably because of the high prevalence of 'resistance-related' mutations at day 0 in the local parasite population. For apparently the same reason, it was not possible to show a statistical association between S/P resistance and the presence of particular polymorphisms in the DHFR and DHPS genes before treatment.

Neuropsychiatric manifestations after mefloquine therapy for Plasmodium falciparum malaria: comparing a retrospective and a prospective study.

UNLABELLED: Mefloquine has been increasingly used for treatment of chloroquine-resistant malaria since its introduction in the late 1970s. In 1987 the first case of toxic encephalopathy was published, and in 1989 the WHO initiated reporting and investigation of neuropsychiatric adverse reactions of mefloquine. Neuropsychiatric adverse drug reactions are now well documented. We compared an open prospective 3 year study including all patients with P. falciparum treated with mefloquine with an earlier published, retrospective study on a comparable population from our department covering the period up to 1989. In the retrospective study neuropsychiatric adverse effects were not specifically asked for, while in the prospective study possible adverse reactions were registered daily according to a specified questionnaire. No case of neuropsychiatric adverse reaction was registered in the retrospective study. In the prospective study, 28% had one or more neuropsychiatric adverse reactions, although severity was mostly mild to moderate. Other adverse reactions occurred in 96% in the retrospective study compared to 81% in the prospective study. IN CONCLUSION: one often finds only what one looks for, e.g adverse events may be overlooked for a decade, if relatively uncommon. This report also shows that retro- and prospective studies may give very different results.

High prevalence of mutations in the dihydrofolate reductase gene of Plasmodium falciparum in isolates from Tanzania without evidence of an association to clinical sulfadoxine/pyrimethamine resistance.

Recently the efficacy of sulfadoxine/pyrimethamine (S/P) in treatment of uncomplicated falciparum malaria in Tanzania has been seriously compromised by the development of resistance. The occurrence of active site mutations in the Plasmodium falciparum gene sequence coding for dihydrofolate reductase (DHFR) is known to confer resistance to pyrimethamine. This study investigates the occurrence of these mutations in infected blood samples taken from Tanzanian children before treatment with S/P and their relationship to parasite breakthrough by day 7. The results confirm the occurrence of one or more DHFR mutations in all the samples, but no relationship was found with the presence of parasites in the blood at day 7. The results suggest that alterations in the coding region for dihydropteroate synthetase (DHPS), the enzyme target for sulfadoxine, should be studied in order to predict resistance to the S/P combination. It has been proposed earlier that sulfadoxine could itself act on DHFR, because of a false dihydrofolate produced by drug metabolism through DHPS and dihydrofolate synthase. The results of this treatment study suggest that such a possibility is unlikely.

Decreased plasma levels of factor II + VII + X correlate with increased levels of soluble cytokine receptors in patients with malaria and meningococcal infections.

The levels of coagulation factors II + VII + X and of blood platelets (thrombocytes) as well as of cytokines and soluble cytokine receptors were studied in the patients with malaria or meningococcal infections. The coagulation factors were decreased particularly in the meningococcal patients, while thrombocytes were lowest in the Plasmodium falciparum malaria patients. There was no correlation between factors II + VII + X and thrombocytes, but plasma levels of coagulation factors II + VII + X were found to correlate inversely with levels of soluble interleukin-2 receptor (sIL-2R) and soluble tumour necrosis factor-I (sTNF-RI) in patients with malaria and meningococcal infections. Elevated sIL-2R and sTNF-RI levels and decreased coagulation factors reverted to normal within 3-5 days after initiation of therapy in P. falciparum patients followed consecutively. Estimation of coagulation factors may be used to monitor the course of these common and potentially life-threatening infections.

Maloprim malaria prophylaxis in children living in a holoendemic village in north-eastern Tanzania.

A randomized, double-'blind', placebo-controlled trial of weekly Maloprim (dapsone-pyrimethamine, D-P) for malaria prophylaxis was conducted at Magoda village in north-eastern Tanzania. The effect of D-P on the incidence of clinical malaria, Plasmodium falciparum prevalence and density, splenomegaly, and packed cell volume (PCV) was investigated in a cohort of 249 children (126 receiving D-P and 123 receiving placebo) aged 1-9 years. The case definition of clinical malaria (malaria fever) was measured axillary temperature > or = 37.5 degrees C and/or reported fever, and P. falciparum asexual parasitaemia > or = 5000/microL. Children aged 1-4 years given D-P experienced 1.56 episodes of clinical malaria per year, whereas children on placebo experienced 2.55 episodes (relative rate [RR] = 0.61, 95% confidence interval [CI] 0.47, 0.80). Thus, D-P protective efficacy against clinical malaria, in this age group, was 39% (95% CI 20%, 53%; P = 0.0002). The annual incidence of clinical malaria among children aged 5-9 years was 0.16 episodes in the D-P group and 0.26 episodes in those receiving placebo (RR = 0.58, 95% CI 0.26, 1.28; P = 0.17). Increased malaria transmission and drug resistance, during the course of the trial, resulted in a reduction in the protective efficacy of D-P. Overall, D-P was able to reduce parasite densities and splenomegaly. D-P prophylaxis also resulted in an increase in PCV but this effect diminished towards the end of the trial. D-P exerted a suppressive effect on asexual parasitaemia throughout the trial.

Comparative biodistribution of meta-Tetra(Hydroxyphenyl) chlorin in multiple species: clinical implications for photodynamic therapy.

BACKGROUND AND OBJECTIVE: To optimize photodynamic therapy, it is necessary to know the distribution of photosensitizer in normal tissue as well as tumors and to know how well animal models match human. This study measured the biodistribution of meta-Tetra(Hydroxyphenyl) Chlorin (mTHPC) in three species of animals and in humans. STUDY DESIGN/MATERIALS AND METHODS: mTHPC was injected intravenously into dogs, rabbits, and humans, and drug levels in various tissues were determined 6 days later. One dog was perfused with 3 L of saline to remove blood trapped within organs. RESULTS: Absolute and relative concentrations of drug in specific tissues varied between species and between individuals. There was a general pattern of distribution. Highly vascularized tissues had the highest levels of mTHPC, not simply due to trapping of blood. mTHPC did not localize in bone and did not cross the blood-brain barrier. Humans had much higher levels of drug in their plasma and tissues than did animals. CONCLUSIONS: First, drug retention varies from one tissue to another. Second, there is significant variability from one individual to another, whether animal or human. Third, current models cannot accurately predict from animal studies the optimum dose for humans. Measurement of photosensitizer level in plasma at time of treatment would allow optimal photodynamic dosing.

Immunoglobulin G reactivities to rhoptry-associated protein-1 associated with decreased levels of Plasmodium falciparum parasitemia in Tanzanian children.

In the Muheza region of Tanzania, an area with holoendemic malaria, the proportion of responders with IgG enzyme-linked immunosorbent assay reactivities to recombinant rhoptry-associated protein-1 (rRAP-1) as well as IgG reactivities to a repeat region of the acidic-basic repeat antigen (ABRA) increased with age. The proportion of responders with IgM reactivities to rRAP-1 increased with age in the first three decades. However, levels of IgG reactivities to rRAP-1 did not increase with age, indicating high levels of reactivities among young children. High P. falciparum densities were only detectable in children less than five years of age; in this group the proportion of IgG responders to rRAP-1 and to the ABRA repeat region was low but levels of IgG reactivities to rRAP-1 were inversely correlated with parasite density, suggesting that immune recognition of the antigen may be associated with resistance to infection. On the other hand, levels of IgG reactivities to the repeat region of ABRA increased with parasite densities in children 1-4 years of age. Two different profiles of IgG reactivities to rRAP-1 and to ABRA are detectable in young Tanzanian children and the Ig reactivities against rRAP-1 may be a component of the immune reactions restricting parasite multiplication.

[Contributing causes of malaria among Danish travellers]. / Medvirkende årsager til malaria blandt danske rejsende.

A retrospective evaluation of contributing causes of malaria among Danish travellers, based on patient files and telephone interviews, is presented. Four centres participated, and 33% of all malaria cases reported to the Danish authorities in 1993 and 1994 were included (in total 82 patients). Ten out of 52 patients with falciparum malaria had not taken any chemoprophylaxis at all. Among the 42 patients who had, only 14 were both correctly advised and fully compliant. Within the remaining 28 patients, lack of compliance concerning the chemoprophylaxis was reported in 16, inadequate chemoprophylaxis was prescribed to 12 patients, and a further eight (19%) were underdosed. Only four out of 30 patients with vivax, ovale or malariae malaria had not used chemoprophylaxis. The distribution of contributing causes of chemoprophylaxis failure was similar to that of falciparum malaria, although noncompliance was more predominant in patients developing vivax, ovale or malariae malaria (58% compared to 38% in falciparum malaria).

High level of resistance of Plasmodium falciparum to sulfadoxine-pyrimethamine in children in Tanzania.

In many areas of tropical Africa affected by chloroquine-resistant Plasmodium falciparum, a combination of sulfadoxine and pyrimethamine (S-P) is used for alternative medication, especially in young children. In Magoda village in Muheza District, north-eastern Tanzania, 38 children 1-10 years of age were enrolled in a therapeutic study of S-P in July 1994. All had monoinfections of P. falciparum and an asexual parasite count of 1000-80,000/microL of blood. S-P was given as a single dose corresponding to 0.8-1.4 mg pyrimethamine/kg body weight. Of the 38 children followed up to day 7, 10 showed an S/RI response, 26 an RII response, and 2 an RIII response. Older children had lower pre-treatment parasitaemia and a better therapeutic response than younger children. Among the various contributory factors responsible for the poor therapeutic result, drug pressure from a prophylactic intervention with weekly dapsone-pyrimethamine between May 1993 and May 1994 seems to have been the most important.