A M el-Hassan

University of Khartoum, Al Kharţūm, Khartoum State, Sudan

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Publications (61)190.67 Total impact

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    ABSTRACT: Post-kala-azar dermal leishmaniasis (PKDL) is a dermatosis that affects more than 50% of successfully treated visceral leishmaniasis (VL) patients in Sudan. PKDL is considered an important reservoir for the parasite and its treatment may help in the control of VL. Currently, treatment is mainly with sodium stibogluconate (SSG), an expensive and fairly toxic drug and without universally in treatment protocols used. A literature review, a consensus of a panel of experts, and unpublished data formed the basis for the development of guidelines for the treatment of PKDL in the Sudan. Six treatment modalities were evaluated. Experts were asked to justify their choices based on their experience regarding of drug safety, efficacy, availability, and cost. The consensus was defined by assigning a categorical rank (first line, second line, third line) to each option. Regarding the use of AmBisome the presence of the drug in the skin was confirmed in smears from PKDL lesions. RECOMMENDATIONS: AmBisome at 2.5 mg/kg/day/20 days or SSG at 20 mg/kg/day/40 days plus four/weekly intradermal injection of alum-precipitated autoclave L. major vaccine are suggested as first- and second-treatment options for PKDL in the Sudan, respectively. SSG at 20 mg/Kg/day/60 or more days can be used if other options are not available.
    Journal of Tropical Medicine 01/2013; 2013:708391.
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    ABSTRACT: Cervical cancer is the most frequent female malignancy in most developing countries. Previous studies have demonstrated a strong association of human papillomavirus (HPV) infection with dysplasia and carcinoma of the uterine cervix. The objective of this study was to identify the prevailing HPV genotypes responsible for the development of cervical cancer among women in Ethiopia and the Sudan. A molecular characterization of HPV was done on 245 paraffin embedded cervical biopsy samples collected from the two countries. Amplification of HPV and subsequent genotyping was done using SPF10 primers and Line probe assay. Of samples collected from Ethiopian patients, 93% (149/160) and 13% (21/160) had high risk and low risk HPV genotypes, respectively. Among samples collected from the Sudan, 94% (80/85) harbored high risk and 11.7% (10/85) low risk HPV genotypes. Human papillomavirus 16 was the most frequent genotype identified in samples from Ethiopia (91%, 136/149) and the Sudan (82.5%, 66/80). HPV 52, 58, and 18 were the second, third and fourth common genotypes identified in Ethiopia, whereas HPV 18, 45, and 52 were the second, third, and fourth genotypes identified in samples collected from the Sudan. Thus, individuals living in different geographical localities should receive vaccines based on the specific genotypes circulating in the area and a vaccine targeting HPV 16, 18, 45, 52, and 58 may be optimal for the control of cervical cancer in the two countries. J. Med. Virol. © 2012 Wiley Periodicals, Inc.
    Journal of Medical Virology 11/2012; · 2.22 Impact Factor
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    ABSTRACT: Alternative treatments for visceral leishmaniasis (VL) are required in East Africa. Paromomycin sulphate (PM) has been shown to be efficacious for VL treatment in India. A multi-centre randomized-controlled trial (RCT) to compare efficacy and safety of PM (20 mg/kg/day for 21 days) and PM plus sodium stibogluconate (SSG) combination (PM, 15 mg/kg/day and SSG, 20 mg/kg/day for 17 days) with SSG (20 mg/kg/day for 30 days) for treatment of VL in East Africa. Patients aged 4-60 years with parasitologically confirmed VL were enrolled, excluding patients with contraindications. Primary and secondary efficacy outcomes were parasite clearance at 6-months follow-up and end of treatment, respectively. Safety was assessed mainly using adverse event (AE) data. The PM versus SSG comparison enrolled 205 patients per arm with primary efficacy data available for 198 and 200 patients respectively. The SSG & PM versus SSG comparison enrolled 381 and 386 patients per arm respectively, with primary efficacy data available for 359 patients per arm. In Intention-to-Treat complete-case analyses, the efficacy of PM was significantly lower than SSG (84.3% versus 94.1%, difference = 9.7%, 95% confidence interval, CI: 3.6 to 15.7%, p = 0.002). The efficacy of SSG & PM was comparable to SSG (91.4% versus 93.9%, difference = 2.5%, 95% CI: -1.3 to 6.3%, p = 0.198). End of treatment efficacy results were very similar. There were no apparent differences in the safety profile of the three treatment regimens. The 17 day SSG & PM combination treatment had a good safety profile and was similar in efficacy to the standard 30 day SSG treatment, suggesting suitability for VL treatment in East Africa. www.clinicaltrials.govNCT00255567.
    PLoS Neglected Tropical Diseases 06/2012; 6(6):e1674. · 4.49 Impact Factor
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    ABSTRACT: This prospective study aimed to determine the safety and efficacy of itraconazole for the treatment of patients with mycetoma due to Madurella mycetomatis. The study consisted of 13 patients with confirmed disease; all were treated with oral itraconazole in a dose of 400mg daily for three months after which the dose was reduced to 200mg daily for nine months. All patients showed good clinical response to 400mg itraconazole daily, but when the dose was reduced to 200mg daily, the clinical response was gradual and slow. Post-treatment surgical exploration showed that, in all patients, the lesions were well localized, encapsulated with thick capsule and they were easily removed surgically. In all these lesions, grains colonies were encountered and they were viable on culture. Post-operative biopsies showed no significant changes in the morphology of the grains. A constant finding was the presence of between 5-7 grains in a single cavity walled by fibrous tissue. The reaction surrounding the grains was a Type I tissue reaction characterized by a neutrophil zone around grains. Patients were followed up post-operatively for variable periods (range 18-36 months) and only one patient had recurrence. Initial pre-operative treatment with itraconazole may be recommended for eumycetoma patients to enhance lesions encapsulation and localization which can facilitate wide local excision to avoid unnecessary massive mutilating surgery and recurrence.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 03/2011; 105(3):127-32. · 1.93 Impact Factor
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    ABSTRACT: A recent study has shown that treatment of visceral leishmaniasis (VL) with the standard dose of 15 mg/kg/day of paromomycin sulphate (PM) for 21 days was not efficacious in patients in Sudan. We therefore decided to test the efficacy of paramomycin for a longer treatment duration (15 mg/kg/day for 28 days) and at the higher dose of 20 mg/kg/day for 21 days. This randomized, open-label, dose-finding, phase II study assessed the two above high-dose PM treatment regimens. Patients with clinical features and positive bone-marrow aspirates for VL were enrolled. All patients received their assigned courses of PM intramuscularly and adverse events were monitored. Parasite clearance in bone-marrow aspirates was tested by microscopy at end of treatment (EOT, primary efficacy endpoint), 3 months (in patients who were not clinically well) and 6 months after EOT (secondary efficacy endpoint). Pharmacokinetic data were obtained from a subset of patients weighing over 30 kg. 42 patients (21 per group) aged between 4 and 60 years were enrolled. At EOT, 85% of patients (95% confidence interval [CI]: 63.7% to 97.0%) in the 20 mg/kg/day group and 90% of patients (95% CI: 69.6% to 98.8%) in the 15 mg/kg/day group had parasite clearance. Six months after treatment, efficacy was 80.0% (95% CI: 56.3% to 94.3%) and 81.0% (95% CI: 58.1% to 94.6%) in the 20 mg/kg/day and 15 mg/kg/day groups, respectively. There were no serious adverse events. Pharmacokinetic profiles suggested a difference between the two doses, although numbers of patients recruited were too few to make it significant (n = 3 and n = 6 in the 20 mg/kg/day and 15 mg/kg/day groups, respectively). Data suggest that both high dose regimens were more efficacious than the standard 15 mg/kg/day PM for 21 days and could be further evaluated in phase III studies in East Africa.
    PLoS Neglected Tropical Diseases 10/2010; 4(10):e855. · 4.49 Impact Factor
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    ABSTRACT: Sudanese visceral leishmaniasis (VL) is a disease of children that is characterized by fever, hepatosplenomegaly, lymphadenopathy, pancytopenia, and renal injury. Microalbuminuria (MA) and urinary retinol binding protein (urRBP) are useful markers for glomerular and tubular dysfunctions, respectively. We report the prevalence of subtle renal injury in 88 parasitologically confirmed VL patients in a cross-sectional and hospital-based study. Blood and urine were collected before treatment for hematological, biochemical profiles in addition to MA and urRBP measurement using competitive solid phase, sandwich enzyme-linked immune sorbent assay (ELISA), and immunoturbidometry. All the patients had normal serum urea and creatinine levels and no detectable urRBP. However, 40% of the patients had MA detected by ELISA, and 42% were reactive with turbidometry. The sensitivity, specificity, positive and negative predictive values for MA turbidometric technique were calculated as 100%; 96%; 95% and 100%, respectively. In conclusion; subtle renal injury in VL is mainly glomerular. Turbidometry for MA measurement is a simple, inexpensive, sensitive, and specific technique with high predictive values.
    Saudi journal of kidney diseases and transplantation: an official publication of the Saudi Center for Organ Transplantation, Saudi Arabia 09/2010; 21(5):872-5.
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    ABSTRACT: Drug unresponsiveness in patients with visceral leishmaniasis (VL) is a problem in many endemic areas. This study aimed to determine genetic diversity of Leishmania donovani isolates from a VL endemic area in Sudan as a possible explanation for drug unresponsiveness in some patients. Thirty clinically stibogluconate (SSG)-sensitive isolates were made SSG-unresponsive in vitro by gradually increasing SSG concentrations. The sensitive isolates and their SSG-unresponsive counterparts were typed using mini-circle kDNA and categorized using PCR-RAPD. All the isolates were typed as L. donovani, the resulting PCR-RAPD characterization of the SSG-sensitive isolates gave three distinct primary genotypes while, the SSG-unresponsive isolates showed only a single band. L. donovani isolates from eastern Sudan are diverse; this probably resulted from emergence of new L. donovani strains during epidemics due to the pressure of widespread use of antimonials. In this communication the possible role of isolates diversity in antimonial unresponsiveness and the in vitro changing PCR-RAPD band pattern in SSG-unresponsive strains were discussed.
    Experimental Parasitology 03/2010; 125(4):389-93. · 1.86 Impact Factor
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    ABSTRACT: Visceral leishmaniasis (VL) is a major health problem in developing countries. The untreated disease is fatal, available treatment is expensive and often toxic, and drug resistance is increasing. Improved treatment options are needed. Paromomycin was shown to be an efficacious first-line treatment with low toxicity in India. This was a 3-arm multicentre, open-label, randomized, controlled clinical trial to compare three treatment regimens for VL in East Africa: paromomycin sulphate (PM) at 15 mg/kg/day for 21 days versus sodium stibogluconate (SSG) at 20 mg/kg/day for 30 days; and the combination of both dose regimens for 17 days. The primary efficacy endpoint was cure based on parasite-free tissue aspirates taken 6 months after treatment. Overall, 135 patients per arm were enrolled at five centres in Sudan (2 sites), Kenya (1) and Ethiopia (2), when the PM arm had to be discontinued due to poor efficacy. The trial has continued with the higher dose of PM as well as the combination of PM and SSG arms. These results will be reported later. Baseline patient characteristics were similar among treatment arms. The overall cure with PM was significantly inferior to that with SSG (63.8% versus 92.2%; difference 28.5%, 95%CI 18.8% to 38.8%, p<0.001). The efficacy of PM varied among centres and was significantly lower in Sudan (14.3% and 46.7%) than in Kenya (80.0%) and Ethiopia (75.0% and 96.6%). No major safety issues with PM were identified. The efficacy of PM at 15 mg/kg/day for 21 days was inadequate, particularly in Sudan. The efficacy of higher doses and the combination treatment warrant further studies.
    PLoS Neglected Tropical Diseases 01/2010; 4(10):e709. · 4.49 Impact Factor
  • Annals of Tropical Medicine and Parasitology 02/2008; 102(1):79-80. · 1.20 Impact Factor
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    ABSTRACT: To determine whether Mycobacterium tuberculosis infection spreads through the blood to different lymph-node groups in patients with tuberculous lymphadenitis. Prospective analytical study. The patients were recruited, managed and followed at the lymphodenopathy clinic, Central Police Hospital, Burr, Khartoum, Sudan. Fifty two sequential patients were enrolled. Thirty patients with FNAC diagnosis of tuberculous lymphadenitis and positive PCR for M. tuberculosis complex had a mean age of 26.9 +/- 11.2 years and similar male, female affection. Nine patients with FNAC tuberculous lymphadenitis, but negative PCR had a slightly higher mean age (32.6 +/- 18.2 years) with similar male: female proportions. Patients with reactive lymphadenopathy (9/52) were older than patients with tuberculous lymphadenitis with a mean age of 45 +/- 24.6 years. None of the patients were positive for HIV or had clinical or radiological evidence of pulmonary tuberculosis. M. tuberculosis DNA was detected in the blood samples of 30/39 (77%) patients with tuberculous lymphadenitis, but in none of the cases with reactive or malignant lymphadenopathy. The presence of M. tuberculosis DNA correlated strongly to multiple lymph-node involvement [OR (odds ratio) = 96.7, 95% confidence interval (CI) 9.0 - 1,039] and to caseating-granulomatous and predominantly necrotic cytomorphological categories [OR = 70, 95% confidence interval (CI) 7.0 - 703]. M. tuberculosis most probably disseminates through the blood from one node group to the other in patients with tuberculous lymphadenitis.
    East African medical journal 02/2007; 84(1):3-7.
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    ABSTRACT: To determine the aetiological types of granulomatous disease of the breast in women presenting with mammary complaints in the Sudan. Clinical history and physical examination, complete blood counts, Mantoux test, histopathology and fine needle aspiration cytology (FNAC). Granulomatous mastitis was seen in 11/2500 (0.44%) patients with mammary disease over a 10-year period. All were of childbearing age (mean 26.0 +/- 5.9 years). Common presentations were diffuse swelling, well-circumscribed masses, nipple retraction, multiple sinuses and superficial skin ulcers. Lymphadenopathy was seen in more than 60% of the patients. Diagnosis was based on cytomorphological features in 10/11 cases and histopathology in one. Nine were diagnosed with tuberculous mastitis and two with idiopathic granulomatous mastitis. Acid-fast bacilli (AFB) could not be demonstrated in any of the cytology smears. Tuberculous mastitis responded to empirical anti-tuberculosis treatment, with a minimum follow-up of 2 years in seven women. Tuberculous mastitis is a rare entity in women with mammary disease in the Sudan. Alternative diagnoses such as idiopathic granulomatous mastitis should be made only after failure of an adequate trial of anti-tuberculosis treatment. FNAC is a useful diagnostic tool even if AFB cannot be demonstrated.
    The International Journal of Tuberculosis and Lung Disease 05/2003; 7(4):365-9. · 2.76 Impact Factor
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    ABSTRACT: Post-kala-azar dermal leishmaniasis (PKDL) is a complication of visceral leishmaniasis (VL); it is characterised by a macular, maculopapular, and nodular rash in a patient who has recovered from VL and who is otherwise well. The rash usually starts around the mouth from where it spreads to other parts of the body depending on severity. It is mainly seen in Sudan and India where it follows treated VL in 50% and 5-10% of cases, respectively. Thus, it is largely restricted to areas where Leishmania donovani is the causative parasite. The interval at which PKDL follows VL is 0-6 months in Sudan and 2-3 years in India. PKDL probably has an important role in interepidemic periods of VL, acting as a reservoir for parasites. There is increasing evidence that the pathogenesis is largely immunologically mediated; high concentrations of interleukin 10 in the peripheral blood of VL patients predict the development of PKDL. During VL, interferon gamma is not produced by peripheral blood mononuclear cells (PBMC). After treatment of VL, PBMC start producing interferon gamma, which coincides with the appearance of PKDL lesions due to interferon-gamma-producing cells causing skin inflammation as a reaction to persisting parasites in the skin. Diagnosis is mainly clinical, but parasites can be seen by microscopy in smears with limited sensitivity. PCR and monoclonal antibodies may detect parasites in more than 80% of cases. Serological tests and the leishmanin skin test are of limited value. Treatment is always needed in Indian PKDL; in Sudan most cases will self cure but severe and chronic cases are treated. Sodium stibogluconate is given at 20 mg/kg for 2 months in Sudan and for 4 months in India. Liposomal amphotericine B seems effective; newer compounds such as miltefosine that can be administered orally or topically are of major potential interest. Although research has brought many new insights in pathogenesis and management of PKDL, several issues in particular in relation to control remain unsolved and deserve urgent attention.
    The Lancet Infectious Diseases 03/2003; 3(2):87-98. · 19.45 Impact Factor
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    ABSTRACT: In a previous efficacy study, autoclaved Leishmania major (ALM) + bacille Calmette-Guérrin (BCG) vaccine was shown to be safe, but not superior to BCG alone, in protecting against visceral leishmaniasis. From June 1999 to June 2000, we studied the safety and immunogenicity of different doses of alum-precipitated ALM + BCG vaccine mixture administered intradermally to evaluate whether the addition of alum improved the immunogenicity of ALM. Twenty-four healthy adult volunteers were recruited and sequentially allocated to receive either 10 microg, 100 microg, 200 microg, or 400 microg of leishmanial protein in the alum-precipitated ALM + BCG vaccine mixture. Side effects were minimal for all doses and confined to the site of injection. All volunteers in the 10 microg, 100 microg, and 400 microg groups had a leishmanin skin test (LST) reaction of > or = 5 mm by day 42 and this response was maintained when tested after 90 d. Only 1 volunteer out of 5 in the 200 microg group had a LST reaction of > or = 5 mm by day 42 and the reasons for the different LST responses in this group are unclear. This is the first time that an alum adjuvant with ALM has been in used in humans and the vaccine mixture was safe and induced a strong delayed type hypersensitivity (DTH) reaction in the study volunteers. On the basis of this study we suggest that 100 1 microg of leishmanial protein in the vaccine mixture is a suitable dose for future efficacy studies, as it induced the strongest DTH reaction following vaccination.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 01/2003; 97(3):365-8. · 1.93 Impact Factor
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    ABSTRACT: Clinical and epidemiological data were collected from 187 clinically diagnosed measles patients in Haj Yousif area, suburban Khartoum. Laboratory tests confirmed the diagnosis in 141 (75%) of the cases, but demonstrated that in 46 (25%) patients the clinical symptoms were not caused by an acute measles virus (MV) infection. According to their vaccination card, 59% of the laboratory-confirmed measles cases had been vaccinated for measles. Compared with non-measles rash disease cases, confirmed measles cases more often had severe illness (P < 0.0001), were dehydrated (P=0.01) at presentation and less likely to recover without complications [OR 0.19 (95% CI 0.09, 0.39)]. There was no difference in death rate (P=0.20). Underweight [weight-for-age Z score (WAZ) <or= -2 SD] was an independent predictor of recovery with complications [OR 0.4 (95% CI 0.2, 0.99)]. Severe measles cases (those who developed diarrhoea, pneumonia, otitis media, encephalitis or haemorrhagic rash) had similar vaccination rates and time intervals since vaccination as uncomplicated measles cases. Although severe measles had lower WAZ-scores (P=0.004), none of the nutritional parameters studied were predictive of outcome. Mortality was higher in the severe measles group [OR 8.8 (95% CI 1.7, 85.2)]. In 11 of 141 confirmed measles cases serological evidence of a recent infection with another virus was found, most commonly varicella zoster virus and dengue virus; spotted fever and rubella were among the most frequent diagnoses in 17 of 47 cases of the non-measles cases.
    Tropical Medicine & International Health 06/2002; 7(5):442-9. · 2.30 Impact Factor
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    ABSTRACT: Clinical and epidemiological data were collected from 187 clinically diagnosed measles patients in Haj Yousif area, suburban Khartoum. Laboratory tests confirmed the diagnosis in 141 (75%) of the cases, but demonstrated that in 46 (25%) patients the clinical symptoms were not caused by an acute measles virus (MV) infection. According to their vaccination card, 59% of the laboratory-confirmed measles cases had been vaccinated for measles. Compared with non-measles rash disease cases, confirmed measles cases more often had severe illness (P < 0.0001), were dehydrated (P=0.01) at presentation and less likely to recover without complications [OR 0.19 (95% CI 0.09, 0.39)]. There was no difference in death rate (P=0.20). Underweight [weight-for-age Z score (WAZ) ≤ −2 SD] was an independent predictor of recovery with complications [OR 0.4 (95% CI 0.2, 0.99)]. Severe measles cases (those who developed diarrhoea, pneumonia, otitis media, encephalitis or haemorrhagic rash) had similar vaccination rates and time intervals since vaccination as uncomplicated measles cases. Although severe measles had lower WAZ-scores (P=0.004), none of the nutritional parameters studied were predictive of outcome. Mortality was higher in the severe measles group [OR 8.8 (95% CI 1.7, 85.2)]. In 11 of 141 confirmed measles cases serological evidence of a recent infection with another virus was found, most commonly varicella zoster virus and dengue virus; spotted fever and rubella were among the most frequent diagnoses in 17 of 47 cases of the non-measles cases.
    Tropical Medicine & International Health 05/2002; 7(5):442 - 449. · 2.30 Impact Factor
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    L A el Hassan, E A G Khalil, A M el-Hassan
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    ABSTRACT: Social and cultural factors influencing knowledge, attitudes and practices (KAP) towards leprosy in two communities in eastern Sudan were studied to determine their effects on treatment seeking and compliance. The study was qualitative using focus small group discussions, personal interviews and direct observation. The target populations were Masalit and Hawsa, the two main tribes in the area. Knowledge about the pathological cause of leprosy was lacking but the clinical manifestations were well recognized, particularly among the Masalit, in whom the disease in more common than the Hawsa. Among the Masalit there was a widely held belief that leprosy was caused by eating meat of the wild pig and a certain type of fish. The Hawsa, who are more devout Muslims, do not eat pig and associate leprosy with consumption of two types of fish. Between both tribes, the stigma of leprosy was not strong and the degree of rejection was more towards those with severe disease, particularly patients with ulcerated lesions and severe deformities. Patients were cared for by the family and lived in a separate hut within the families' housing compounds. In this remote area where medical services are scarce or nonexistent, those interviewed did not realize that leprosy was treatable by modern medicine. This influenced the treatment-seeking behaviour of patients, who were often treated by spiritual healers and other traditional medicine practices. With the introduction of multidrug therapy and health education of patients and society, many more patients are now seeking medical treatment, indicating a change in health seeking behaviour.
    Leprosy review 04/2002; 73(1):20-8. · 0.59 Impact Factor
  • E E Zijlstra, A M el-Hassan
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    ABSTRACT: Post kala-azar dermal leishmaniasis (PKDL) is increasingly recognized in Sudan as a complication of visceral leishmaniasis (VL), occurring in c. 55% of patients after, or during treatment of, VL. The development of PKDL seems to be restricted to parasites of the Leishmania donovani sensu stricto cluster; no particular zymodeme has been found to be associated with it. In contrast to PKDL in India, PKDL in Sudan occurs within 0-6 months after treatment for VL. The rash may be macular, maculo-papular or nodular, and spreads from the perioral area to other parts of the body, depending on grade of severity. Young children are particularly at risk of developing more severe disease. In 16% of PKDL patients, parasites can be demonstrated by microscopy in lymph node or bone marrow aspirates and, with the aid of the polymerase chain reaction (PCR), in lymph nodes of 81% of patients, possibly indicating persistent visceralized infection. Diagnosis can be made by demonstration of parasites in skin smears or biopsies in 20-30% of cases; newer techniques, using PCR with skin smears, have higher sensitivity (83%). Monoclonal antibodies against L. donovani can detect parasites in 88% of biopsies. Serological tests are of limited value. The leishmanin skin test is positive in 50-60% of cases; there is an inverse relationship between the skin test result and severity of PKDL. In differential diagnosis, miliaria rubra is the most common problem; differentiation from leprosy is the most difficult. In biopsies, hyperkeratosis, parakeratosis, acanthosis, follicular plugging and liquefaction degeneration of the basal layer may be found in the epidermis; in the dermis there are varying intensities of inflammation with scanty parasites and mainly lymphocytes; macrophages and epithelioid cells may also be found. In 20% of cases discrete granulomas may be found. After VL, the immune response shifts from a Th2-type to a mixed Th1/Th2-type. High levels of interleukin-10 in skin biopsies as well as in peripheral blood mononuclear cells and plasma in patients with VL predict the development of PKDL. Treatment is needed only for those who have severe and prolonged disease; sodium stibogluconate (20 mg/kg/d for 2 months) is usually sufficient. (Liposomal) amphotericin B is effective, whereas ketoconazole, terbinafine and itraconazole are not.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 05/2001; 95 Suppl 1:S59-76. · 1.93 Impact Factor
  • A M el-Hassan, E E Zijlstra
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    ABSTRACT: Cutaneous leishmaniasis (CL) in Sudan is caused by Leishmania major, zymodeme LON-1. The disease is endemic in many parts of the country. The vector is Phlebotomus papatasi and the animal reservoir is probably the Nile rat Arvicanthis niloticus. Clinically, patients usually present with papules, nodules, or nodulo-ulcerative lesions, mainly on the exposed parts of the skin. In 20% of cases the parasite disseminates through the lymphatics, producing sporotrichoid-like lesions. The pathology of the lesion is described. Langerhans cells are the main antigen-presenting cells in CL. They pickup antigen from the dermis and migrate to regional lymph nodes where they present it to T cells. Antigen-specific activated T cells home to the dermis where they stimulate macrophages to eliminate the parasite. Peripheral blood mononuclear cells (PBMC) proliferate in response to Leishmania antigen in vitro and produce cytokines. PBMC of patients with mild and severe disease produce Th1- and Th2-like cytokine patterns, respectively. The criteria for the clinical diagnosis of CL are described. The diagnosis is confirmed by the demonstration of parasites in slit smears in 50-70% of cases and in histological sections in 70%. With primers specific for L. major, the polymerase chain reaction is positive in 86% of cases. Since CL is a self-limiting disease, treatment is confined to patients with severe disease.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 05/2001; 95 Suppl 1:S1-17. · 1.93 Impact Factor
  • E E Zijlstra, A M el-Hassan
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    ABSTRACT: From the early 1900s, visceral leishmaniasis (VL; kala-azar) has been among the most important health problems in Sudan, particularly in the main endemic area in the eastern and central regions. Several major epidemics have occurred, the most recent--in Western Upper Nile province in southern Sudan, detected in 1988--claiming over 100,000 lives. The disease spread to other areas that were previously not known to be endemic for VL. A major upsurge in the number of cases was noted in the endemic area. These events triggered renewed interest in the disease. Epidemiological and entomological studies confirmed Phlebotomus orientalis as the vector in several parts of the country, typically associated with Acacia seyal and Balanites aegyptiaca vegetation. Infection rates with Leishmania were high, but subject to seasonal variation, as were the numbers of sand flies. Parasites isolated from humans and sand flies belonged to three zymodemes (MON-18, MON-30 and MON-82), which all belong to the L. donovani sensu lato cluster. Transmission dynamics have not been elucidated fully; heavy transmission in relatively scarcely populated areas such as Dinder national park suggested zoonotic transmission whereas the large numbers of patients with post kala-azar dermal leishmaniasis (PKDL) in heavily affected villages may indicate a human reservoir and anthroponotic transmission. Clinical presentation in adults and in children did not differ significantly, except that children were more anaemic. Fever, weight loss, hepato-splenomegaly and lymphadenopathy were the most common findings. PKDL was much more common than expected (56% of patients with VL developed PKDL), but other post-VL manifestations were also found affecting the eyes (uveitis, conjunctivitis, blepharitis), nasal and/or oral mucosa. Evaluation of diagnostic methods showed that parasitological diagnosis should still be the mainstay in diagnosis, with sensitivities for lymph node, bone marrow and spleen aspirates of 58%, 70% and 96%, respectively. Simple, cheap serological tests are needed. The direct agglutination test (DAT) had a sensitivity of 72%, specificity of 94%, positive predictive value of 78% and negative predictive value of 92%. As with other serological tests, the DAT cannot distinguish between active disease, subclinical infection or past infection. The introduction of freeze-dried antigen and control sera greatly improved the practicality and accuracy of the DAT in the field. An enzyme-linked immunosorbent assay using recombinant K39 antigen had higher sensitivity than DAT (93%). The polymerase chain reaction using peripheral blood gave a sensitivity of 70-93% and was more sensitive than microscopy of lymph node or bone marrow aspirates in patients with suspected VL. The leishmanin skin test (LST) was typically negative during active VL and converted to positive in c. 80% of patients 6 months after treatment. Immunological studies showed that both Th1 and Th2 cell responses could be demonstrated in lymph nodes from VL patients as evidenced by the presence of messenger ribonucleic acid for interleukin (IL)-10, interferon gamma and IL-2. Treatment of peripheral blood mononuclear cells from VL patients with IL-12 was found to drive the immune response toward a Th1 type response with the production of interferon gamma, indicating a potential therapeutic role for IL-12. VL responded well to treatment with sodium stibogluconate, which is still the first line drug at a dose of 20 mg/kg intravenously or intramuscularly per day for 15-30 d. Side effects and resistance were rare. Liposomal amphotericin B was effective, with few side effects. Control measures have not been implemented. Based on observations that VL does not occur in individuals who have a positive LST, probably because of previous cutaneous leishmaniasis, a vaccine containing heat-killed L. major promastigotes is currently undergoing a phase III trial.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 05/2001; 95 Suppl 1:S27-58. · 1.93 Impact Factor
  • A.M. El-Hassan, E.E. Zijlstra
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    ABSTRACT: Sudanese mucosal leishmaniasis is a chronic infection of the upper respiratory tract and/or oral mucosa caused mainly by Leishmania donovani. The disease occurs in areas of the country endemic for visceral leishmaniasis, particularly among Masalit and other closely related tribes in western Sudan. The condition may develop during or after an attack of visceral leishmaniasis, but in most cases it is a primary mucosal disease. Unlike South American mucocutaneous leishmaniasis, mucosal leishmaniasis in Sudan is not preceded or accompanied by a cutaneous lesion. Pathologically, the lesions show a mixture of macrophages, plasma cells and lymphocytes. An epithelioid granuloma may also be found. Parasites are scanty. Diagnosis is established by demonstration of parasites in smears or biopsies, by culture or animal inoculation, or with the aid of the polymerase chain reaction. Most patients give positive results in the direct agglutination test and leishmanin skin test. Patients respond well to treatment with pentavalent antimony compounds.
    Transactions of the Royal Society of Tropical Medicine and Hygiene 04/2001; 95:S19–S26. · 1.93 Impact Factor

Publication Stats

2k Citations
190.67 Total Impact Points

Institutions

  • 1991–2013
    • University of Khartoum
      • • Institute of Endemic Diseases
      • • Department of Zoology
      • • Department of Surgery
      • • Department of Medicine
      • • Faculty of Medicine
      Al Kharţūm, Khartoum State, Sudan
  • 2007
    • Federal Ministry of Health, Sudan
      Al Kharţūm, Khartoum State, Sudan
  • 1993–2003
    • Veterinary Research Institute, Khartoum, Sudan
      Al Kharţūm, Khartoum State, Sudan
  • 2002
    • Ahfad University for Women
      Umm Durmān, Khartoum State, Sudan
  • 1998
    • Academisch Medisch Centrum Universiteit van Amsterdam
      • Department of Infectious Diseases
      Amsterdamo, North Holland, Netherlands
    • University of Amsterdam
      Amsterdamo, North Holland, Netherlands
  • 1997
    • Royal Tropical Institute
      • Department of Biomedical Research
      Amsterdam, North Holland, Netherlands
  • 1995
    • Juba National University (Juba City)
      Al Kharţūm, Khartoum State, Sudan