Studies on the leishmaniases in the Sudan. 2. Clinical and parasitological studies on cutaneous leishmaniasis

Cutaneous Leishmaniasis Prevalence and Clinical Overview: A Single Center Study from Saudi Arabia, Eastern Region, Al-Ahsa

Cutaneous leishmaniasis (CL) is a vector-borne parasitic disease that is transmitted via the bites of infected female sandflies. CL has been endemic in several countries worldwide for many decades, and numerous cases have been reported in Saudi Arabia, particularly across six regions; one of which is AL-Ahsa. Our research aimed to evaluate the epidemiological situation of CL among the patients in Al-Ahsa, Eastern region, Kingdom of Saudi Arabia, during the period from 2017 to 2023. The data were collected from the patients' registries and included 245 patients who were diagnosed with CL in Al-Ahsa, Saudi Arabia. Fewer than half of the cases (47.8%) were Saudi patients, with a significant number of them being males (84.5%). Over half of the cases (52.7%) were aged between 21 and 40 years, and about three-quarters (74.7%) of the cases resided in rural areas. Regarding the nature of the lesions, 38.4% of the cases had one lesion, which was mainly distributed on a lower extremity (62.0%) or an upper extremity (52.2%). A high percentage of the lesions (75.2%) were wet lesions and caused by L. major. Concerning risk factors, a greater number of patients (71.4%) had been in rural areas within the last three months. Additionally, more than half of the cases (54.3%) had close contact with rodents, followed by birds (28.2%), sheep (22.0%), dogs (16.3%), and other animals (1.2%). The results showed a low number of reported CL cases in 2020 and 2021, followed by a surge in 2022 and 2023. The study shows that cutaneous leishmaniasis is still a public health problem in Al-Ahsa and is primarily associated with rural areas.

Microbial perils of the tropics: A case of cutaneous leishmaniasis in an immigrant from South America

Cutaneous leishmaniasis is an important cause of nonhealing lesions in those recently immigrated to the United States from endemic areas. The lesions can present with various characteristics such as ulcerations, macules, or papules, and may be painful or painless. Several diagnostic modalities, including polymerase chain reaction testing, should be performed to identify the causative Leishmania species which is important in determining appropriate treatment. We describe a case of cutaneous leishmaniasis caused by Leishmania panamensis in a patient who recently traveled through South and Central America.

Cutaneous sporotrichoid leishmaniasis: An atypical case caused by Leishmania major

A 32 year-old male was referred in our institution for painless erythematous papules on the back of the right hand, treated by various local therapies with no noticeable benefits. On examination multiples inconspicuous nodules were identified 10 days after the onset of the primary lesion. Mycological examination was done to rule out sporotrichosis, then cutaneous leishmaniasis was retained by finding amastigotes forms, and Leishmania major agent was confirmed after culture on NNN medium followed by isoenzyme electrophoresis. Sporortrichoid leishmaniasis is a rare condition and usually due to extension of local leishmaniasis into the subcutaneous tissue via direct extension, bloodstream or lymphatics. The patient responded favorably to Meglumine antimoniate treatment. To our knowledge, sporotrichoid cutaneous leishmaniasis after an erythematous-papular onset has never been reported in Algeria, this clinical entity should be considered for an earlier diagnosis and specific therapy.

Leishmania and its relationships with bacteria

Leishmaniasis is a zoonotic and neglected disease, which represents an important public health problem worldwide. Different species of Leishmania are associated with different manifestations, and a practical problem that can worsen the condition of hosts infected with Leishmania is the secondary infection caused by bacteria. This review aims to examine the importance and prevalence of bacteria co-infection during leishmaniasis and the nature of this ecological relationship. In the cases discussed in this review, the facilitation phenomenon, defined as any interaction where the action of one organism has a beneficial effect on an organism of another species, was considered in the Leishmania-bacteria interaction, as well as the effects on one another and their consequences for the host.

Epidemiological and molecular investigation of resurgent cutaneous leishmaniasis in Sudan

OBJECTIVES

Local health personnel have drawn attention to an apparent increase in incidence and severity of cutaneous leishmaniasis (CL) in Sudan. The objective of this study was to investigate CL burden and surveillance.

METHODS

Surveillance data were compiled from the KalaCORE programme, Leishmania coordinators in Northern Kordofan and Southern Darfur, and Khartoum Dermatology Hospital. CL lesions were sampled from 14 suspected cases from Northern Kordofan and the Hospital for Tropical Diseases in Omdurman. PCR-restriction fragment length polymorphism analysis and multilocus sequencing were used to characterize the disease agent.

RESULTS

All sites reported substantial increases from 2014 to 2016/7, far exceeding World Health Organization case reports for 2014, consistent with a widespread outbreak. Single seasonal peak incidence was observed, except for two peaks in Southern Darfur. In Northern Kordofan, the odds ratio for CL in the 35-44 years age group was 2.6 times higher than in the >45 years age group (p<0.0001); in Southern Darfur, the OR was 2.38 greater in males than females (p<0.0001). Lesions included severe presentations, despite chemotherapy. Leishmania major was identified as the agent.

CONCLUSIONS

Active surveillance is required to understand the extent of CL in Sudan, as well as training to standardize surveillance, diagnosis, reporting, and quality control. Point-of-care rapid diagnosis would be valuable. Genotyping and phenotyping are required to monitor the emergence of pathogenic strains, drug resistance, outbreaks, and changes in severity.

Contribution of spinal cord glial cells to L. amazonensis experimental infection-induced pain in BALB/c mice

Background

The cellular and molecular pathophysiological mecha\nisms of pain processing in neglected parasitic infections such as leishmaniasis remain unknown. The present study evaluated the participation of spinal cord glial cells in the pathophysiology of pain induced by Leishmania amazonensis infection in BALB/c mice.

Methods

Mice received intra-plantar (i.pl.) injection of L. amazonensis (1 × 10⁵) and hyperalgesia, and paw edema were evaluated bilaterally for 40 days. The levels of TNF-α and IL-1β, MPO activity, and histopathology were assessed on the 40th day. ATF3 mRNA expression was assessed in DRG cells at the 30th day post-infection. Blood TNF-α and IL-1β levels and systemic parasite burden were evaluated 5–40 days after the infection. At the 30th day post-infection L. amazonensis, the effects of intrathecal (i.t.) treatments with neutralizing antibody anti-CX₃CL1, etanercept (soluble TNFR2 receptor), and interleukin-1 receptor antagonist (IL-1ra) on infection-induced hyperalgesia and paw edema were assessed. In another set of experiments, we performed a time course analysis of spinal cord GFAP and Iba-1 (astrocytes and microglia markers, respectively) and used confocal immunofluorescence and Western blot to confirm the expression at the protein level. Selective astrocyte (α-aminoadipate) and microglia (minocycline) inhibitors were injected i.t. to determine the contribution of these cells to hyperalgesia and paw edema. The effects of i.t. treatments with glial and NFκB (PDTC) inhibitors on spinal glial activation, TNF-α, IL-1β, CX₃CR1 and CX₃CL1 mRNA expression, and NFκB activation were also evaluated. Finally, the contribution of TNF-α and IL-1β to CX₃CL1 mRNA expression was investigated.

Results

L. amazonensis infection induced chronic mechanical and thermal hyperalgesia and paw edema in the infected paw. Mechanical hyperalgesia was also observed in the contralateral paw. TNF-α, IL-1β, MPO activity, and epidermal/dermal thickness increased in the infected paw, which confirmed the peripheral inflammation at the primary foci of this infection. ATF3 mRNA expression at the ipsilateral DRG of the infected paw was unaltered 30 days post-infection. TNF-α and IL-1β blood levels were not changed over the time course of disease, and parasitism increased in a time-dependent manner in the ipsilateral draining lymph node. Treatments targeting CX₃CL1, TNF-α, and IL-1β inhibited L. amazonensis-induced ongoing mechanical and thermal hyperalgesia, but not paw edema. A time course of GFAP, Iba-1, and CX₃CR1 mRNA expression indicated spinal activation of astrocytes and microglia, which was confirmed at the GFAP and Iba-1 protein level at the peak of mRNA expression (30th day). Selective astrocyte and microglia inhibition diminished infection-induced ipsilateral mechanical hyperalgesia and thermal hyperalgesia, and contralateral mechanical hyperalgesia, but not ipsilateral paw edema. Targeting astrocytes, microglia and NFκB diminished L. amazonensis-induced GFAP, Iba-1, TNF-α, IL-1β, CX₃CR1 and CX₃CL1 mRNA expression, and NFκB activation in the spinal cord at the peak of spinal cord glial cells activation. CX₃CL1 mRNA expression was also detected in the ipsilateral DRG of infected mice at the 30th day post-infection, and the i.t. injection of TNF-α or IL-1β in naïve animals induced CX₃CL1 mRNA expression in the spinal cord and ipsilateral DRG.

Conclusions

L. amazonensis skin infection produces chronic pain by central mechanisms involving spinal cord astrocytes and microglia-related production of cytokines and chemokines, and NFκB activation contributes to L. amazonensis infection-induced hyperalgesia and neuroinflammation.

Electronic supplementary material

The online version of this article (10.1186/s12974-019-1496-2) contains supplementary material, which is available to authorized users.

Prevalence of Cutaneous Leishmaniasis in Western Highlands in Yemen

Leishmaniasis in Yemen is still not fully investigated nor well studied. Recently, outbreaks of cutaneous leishmaniasis (CL) in western highland were declared. However, there are no reports concerning the disease and the circulating species in the region. The aim of this study was to determine the prevalence of cutaneous leishmaniasis in Utmah district located in Western Highlands in Yemen. A cross-sectional survey was carried out at those highlands. For the survey, 1165 participants were subjected to Leishmanin Skin Test (LST) accompanied with direct interviews and physical examination. The overall prevalence of cutaneous leishmaniasis in the district was 18.5% and the cutaneous leishmaniasis (CL) was more frequent in the escarpments with a prevalence of 37%, including 5.5% for active lesion and 31.5% for scar of healed lesions. Children under the age of 16 years old comprised most of the CL cases (76.3%). The escarpments of western highlands in Yemen were hyperendemic areas for CL and the infection was more prevalent in children.

Uncharted territory of the epidemiological burden of cutaneous leishmaniasis in sub-Saharan Africa-A systematic review

INTRODUCTION

Cutaneous leishmaniasis (CL) is the most frequent form of leishmaniasis, with 0.7 to 1.2 million cases per year globally. However, the burden of CL is poorly documented in some regions. We carried out this review to synthesize knowledge on the epidemiological burden of CL in sub-Saharan Africa.

METHODS

We systematically searched PubMed, CABI Global health, Africa Index Medicus databases for publications on CL and its burden. There were no restrictions on language/publication date. Case series with less than ten patients, species identification studies, reviews, non-human, and non-CL focused studies were excluded. Findings were extracted and described. The review was conducted following PRISMA guidelines; the protocol was registered in PROSPERO (42016036272).

RESULTS

From 289 identified records, 54 met eligibility criteria and were included in the synthesis. CL was reported from 13 of the 48 sub-Saharan African countries (3 eastern, nine western and one from southern Africa). More than half of the records (30/54; 56%) were from western Africa, notably Senegal, Burkina Faso and Mali. All studies were observational: 29 were descriptive case series (total 13,257 cases), and 24 followed a cross-sectional design. The majority (78%) of the studies were carried out before the year 2000. Forty-two studies mentioned the parasite species, but was either assumed or attributed on the historical account. Regional differences in clinical manifestations were reported. We found high variability across methodologies, leading to difficulties to compare or combine data. The prevalence in hospital settings among suspected cases ranged between 0.1 and 14.2%. At the community level, CL prevalence varied widely between studies. Outbreaks of thousands of cases occurred in Ethiopia, Ghana, and Sudan. Polymorphism of CL in HIV-infected people is a concern. Key information gaps in CL burden here include population-based CL prevalence/incidence, risk factors, and its socio-economic burden.

CONCLUSION

The evidence on CL epidemiology in sub-Saharan Africa is scanty. The CL frequency and severity are poorly identified. There is a need for population-based studies to define the CL burden better. Endemic countries should consider research and action to improve burden estimation and essential control measures including diagnosis and treatment capacity.

Leishmania infection: painful or painless?

The complex life cycle and immunopathological features underpinning the interaction of Leishmania parasites and their mammalian hosts poses frequent poorly explored and inconclusively resolved questions. The altered nociceptive signals over the course of leishmaniasis remain an intriguing issue for nociceptive and parasitology researchers. Experimental investigations have utilized behavioral, morphological, and neuro-immune approaches in the study of experimental cutaneous leishmaniasis (CL). The data generated indicates new venues for the study of the pathological characteristics of nociceptive processing in this parasitic disease. Leishmania-induced pain may be easily observed in mice and rats. However, nociceptive data is more complex in human investigations, including the occurrence of painless lesions in mucocutaneous and cutaneous leishmaniasis. Data from recent decades indicate that humans can also be affected by pain-related symptoms, often distinct from the region of body infection. The molecular and cellular mechanisms underlying such variable nociceptive states in humans during the course of leishmaniasis are an active area of research. The present article reviews nociception in leishmaniasis, including in experimental models of CL and clinical reports.

Therapeutic options for old world cutaneous leishmaniasis and new world cutaneous and mucocutaneous leishmaniasis

Estimated worldwide incidence of tegumentary leishmaniasis (cutaneous leishmaniasis [CL] and mucocutaneous leishmaniasis [MCL]) is over 1.5 million cases per year in 82 countries, with 90 % of cases occurring in Afghanistan, Brazil, Iran, Peru, Saudi Arabia and Syria. Current treatments of CL are poorly justified and have sub-optimal effectiveness. Treatment can be based on topical or systemic regimens. These different options must be based on Leishmania species, geographic regions, and clinical presentations. In certain cases of Old World CL (OWCL), lesions can spontaneously heal without any need for therapeutic intervention. Local therapies (thermotherapy, cryotherapy, paromomycin ointment, local infiltration with antimonials) are good options with less systemic toxicity, reserving systemic treatments (azole drugs, miltefosine, antimonials, amphotericin B formulations) mainly for complex cases. The majority of New World CL (NWCL) types require systemic treatment (mainly with pentavalent antimonials), either to speed the healing or to prevent dissemination to oral-nasal mucosa as MCL (NWMCL). These types of lesions are potentially serious and always require systemic-based regimens, mainly antimonials and pentamidine; however, the associated immunotherapy is promising. This paper is an exhaustive review of the published literature on the treatment of OWCL, NWCL and NWMCL, and provides treatment recommendations stratified according to their level of evidence regarding the species of Leishmania implicated and the geographical location of the infection.

Isolation of bacteria causing secondary bacterial infection in the lesions of Cutaneous Leishmaniasis

Background:

Cutaneous Leishmaniasis (CL) is a parasitic disease characterized by single or multiple ulcerations. Secondary bacterial infection is one of the complications of the disease that can increase the tissue destruction and the resulting scar.

Objective:

To effectively determine the incidence of real secondary bacteria infection in cutaneous leishmaniasis, we designed the current study.

Methods and Materials:

This was a cross-sectional study performed in Skin Diseases and Leishmaniasis Research Centre, Isfahan, Iran. In this study, 854 patients with confirmed CL were enrolled. Samples were taken from all the patients. Sterile swaps were achieved for the ulcer exudates and scraping was used for nonulcerated lesions. All the samples were transferred to tryptic soy broth medium. After 24 h of incubation in 37°C, they were transferred to eosin methylene blue agar (EBM) and blood agar. Laboratory tests were used to determine the species of bacteria. All of the collected data were analyzed by SPSS software and chi-square.

Results:

Among 854 patients with confirmed cutaneous leishmaniasis, 177 patients (20.7%) had positive cultures for secondary bacterial infection. Bacteria isolated from the lesions were as follows: Staphylococcus aureus - 123 cases (69.4%), coagulase negative Staphylococcus - 41 cases (23.1%), E. coil - 7 cases (3.9%), Proteus - 3 cases (1.7%) and Klebsiella - 3 cases (1.7%).

Conclusions:

The incidence of secondary bacterial infection in lesions of CL was 20.7%. The most common isolated pathogen was Staphylococcus aureus. The incidence of secondary bacterial infection was significantly more in the ulcerated lesions as compared with nonulcerated lesions (P = 0.00001).

Distribution frequency of pathogenic bacteria isolated from cutaneus leishmaniasis lesions

Cutaneous leishmaniasis (CL) is a parasitic disease characterized by single or multiple ulcerations. Secondary bacterial infections are one of the complications that can increase the tissue destruction and the resulting scar. To better determine the incidence of real secondary bacterial infections in CL, we designed the current study. This was a cross-sectional study performed in Skin Diseases and Leishmaniasis Research Centre, Isfahan, Iran. A total of 1,255 patients with confirmed CL enrolled in the study. Sterile swaps were achieved for ulcer exudates and scraping was used for non-ulcerated lesions. All samples were transferred to tryptic soy broth medium. After 24 hr of incubation at 37 degrees C they were transferred to eosin methylene blue agar (EMB) and blood agar. Laboratory tests were used to determine the species of bacteria. Among 1,255 confirmed CL patients, 274 (21.8%) had positive cultures for secondary bacterial infections. The bacteria isolated from the lesions were Staphylococcus aureus in 190 cases (69.3%), coagulase negative Staphylococcus in 63 cases (23.0%), E. coli in 10 cases (3.6%), Proteus sp. in 6 cases (2.2%), and Klebsiella sp. in 5 cases (1.9%). The results show that the overall incidence of secondary bacterial infections in the lesions of CL was 21.8%, considerably high. The incidence of secondary bacterial infections was significantly higher in ulcerated lesions compared with non-ulcerated lesions.

Secondary cicatricial and other permanent alopecias

Various nonfollicular scalp conditions can cause secondary scarring or permanent alopecia. Possible causes are congenital defects, trauma, inflammatory conditions, infections, and neoplasms (rarely drugs). Associated signs and symptoms and other diagnostic procedures such as histopathology may aid in the diagnosis. Detection of the underlying disorder may be difficult in end-stage lesions. Treatment is specific for active conditions. Surgery and hair transplantation are options for localized scars.

Uncommon clinical presentations of cutaneous leishmaniasis in Sudan

Cutaneous leishmaniasis in Sudan is caused by Leishmania major zymodeme LON1. Self-healing usually occurs within 1 year but occasionally its duration is prolonged and treatment is required. The clinical forms are ulcers, nodules and noduloulcerative lesions. Here we describe seven patients with uncommon lesions that were difficult to recognize as Leishmania infections. These included mycetoma-like lesions, lesions that resembled L. tropica infection and others. One HIV/AIDS patient had Kaposi's sarcoma with Leishmania parasites in the Kaposi lesions. Most of these uncommon clinical forms were difficult to treat. The diagnosis depended on a high degree of suspicion and the demonstration of parasites in smears or culture. PCR was used to characterize parasites from the patients described here. Leishmania major was found by kDNA PCR in all patients, except one, who had a leishmanioma due to L. donovani. In three patients, including one with a L. tropica like-lesion, the parasites were confirmed as L. major by gp63 PCR-RFLP.

Clinical and histopathological features of zoonotic cutaneous leishmaniasis in Saudi Arabia

BACKGROUND

Zoonotic cutaneous leishmaniasis (ZCL) caused by Leishmania major is a growing public health problem and endemic in many parts of the Kingdom of Saudi Arabia. The vector is Phlebotomus papatasi and the animal reservoirs are mainly desert rodents.

METHODS

In this prospective study, the clinical and histopathological features of ZCL in 120 patients are described and classified. The majority of these patients (n = 84) were non-Saudi expatriate workers who suffered mostly from multiple and severely inflamed nodulo-ulcerative lesions on the exposed parts of the body. Saudi patients were mainly children (n = 21) with few(1-3) lesions on their limbs or sometimes unique erysipeloid facial lesions.

RESULTS

Histopathological grouping of ZCL lesions showed four types of granulomatous reactions based on the predominant types of inflammatory cells, presence or absence of necrosis and ranking of parasitic index.

CONCLUSION

A possible correlation between histopathologic evolution of ZCL lesions and the immune status of the host is discussed.

Therapy of cutaneous leishmaniasis

There have been many treatment modalities used for the therapy of cutaneous leishmaniasis. Although treatment need not be given for cosmetically insignificant lesions, which are often self-limited, therapy is usually indicated for larger, cosmetically significant and disfiguring lesions, and lesions which progress. This review summarizes the published evidence in support of the numerous therapeutic options that have been employed for cutaneous leishmaniasis.

The sandfly fauna in the visceral-leishmaniasis focus of Gedaref, in the Atbara-River area of eastern Sudan

Visceral leishmaniasis (VL) is an acute public-health problem in Sudan. Between 1997 and 2000, four, brief entomological surveys were carried out in Barbar El Fugarra, a village in the state of Gedaref, in the Atbara-River area of eastern Sudan. Between 1996 and 1999, 658 cases of VL occurred among the village's population of about 4000. CDC miniature light-traps set inside and outside human dwellings were used to collect a total of 12,745 sandflies, including five species of the genus Phlebotomus and 19 of Sergentomyia. Phlebotomus papatasi and P. orientalis made up 7% and 5% of the collected sandflies, respectively. Seasonal variation was observed in the numbers of P. orientalis, P. papatasi, S. schwetzi and S. magna caught. Almost all (88%) of the sandflies collected were caught inside houses or granaries and there appeared to be particularly large indoor populations of P. orientalis, P. papatasi, S. schwetzi, S. magna and S. clydei. Phlebotomus orientalis could be responsible for the indoor transmission of the parasites causing the local VL, between humans and between humans and local dogs (which have been found infected by some of the Leishmania zymodemes found in humans). The co-occurrence in this focus of P. papatasi and Arvicanthis niloticus, which are known vectors and reservoir hosts, respectively, of L. major, indicates the possibility that outbreaks of human cutaneous leishmaniasis might occur in the area.

Humoral and cellular immune responses to glucose regulated protein 78 -- a novel Leishmania donovani antigen

The recently cloned glucose regulated protein 78 (GRP78) of Leishmania donovani has been suggested as a new and promising Leishmania vaccine candidate. We assessed antibody and T-cell reactivity to GRP78 in an enzyme-linked immunosorbent assay (ELISA) and in lymphoproliferative assays. Serological evaluation of plasma samples obtained in Sudan revealed that 89% of patients with visceral leishmaniasis (VL), 78% with post kala-azar dermal leishmaniasis (PKDL), and 85% with cutaneous leishmaniasis (CL) had antibody reactivity to this Leishmania antigen. Plasma from healthy Sudanese individuals living in an area endemic for malaria but free of leishmaniasis and plasma from healthy Danes was negative in the assay. GRP78 antibody was detected in 10% and 5% of plasma samples from Sudanese and Ghanaian malaria patients, respectively, whereas 35% of plasma samples from otherwise healthy Sudanese individuals with a positive leishmanin skin test showed antibody reactivity to recombinant GRP78 (rGRP78). In lymphoproliferative assays, 9 of 13 isolates of peripheral blood mononuclear cells (PBMC) from individuals previously infected with L. donovani and one of three individuals previously infected with L. major showed a response to rGRP78, whereas PBMC isolates from Danish control individuals did not respond. These findings, in addition to our previous observations in experimental CL (Jensen et al. 2001), confirm GRP78 as a possible vaccine antigen.

1. Cutaneous leishmaniasis

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.

Leishmaniasis in the Sudan: a literature review with emphasis on clinical aspects

The literature on the leishmaniases in the Sudan is reviewed with an emphasis on clinical aspects and on literature related to the recent outbreaks in the south and east of the country. The numbers of cases of subclinical infection and post-kala azar dermal leishmaniasis in the recent outbreaks are remarkable. New diagnostic techniques have been introduced and evaluated, notably the direct agglutination test and polymerase chain reaction technology. The latter gives very promising results and further research into application of the technique is warranted. Treatment with pentavalent antimony is still satisfactory. The reservoir host has not been identified definitely.

Characterization of the local and systemic immune responses in patients with cutaneous leishmaniasis due to Leishmania major

In this study skin biopsies and peripheral blood samples were obtained from patients with cutaneous leishmaniasis caused by Leishmania major. Samples were obtained at diagnosis and during healing when the lesions had regressed to half the original size. At diagnosis most of the cells expressed HLA-DR. The numbers of CD8+ cells in the lesions were higher at diagnosis than during healing. By contrast, a lower percentage of PBMC expressed CD8+ cells at diagnosis probably due to sequestration in the lesion. In the lesion, in situ staining for IFN-gamma, IL-10, and IL-4 showed marked variation between all patients in the number of positive cells for a particular cytokine. The proliferative response of PBMC to leishmanial antigens and IFN-gamma production tended to increase during healing. Cytokine patterns in the PBMC in response to Leishmania antigen was more specific than in the lesion and correlated better with the clinical manifestations. Possible reasons for this are discussed.

Impact of pyrethroid-impregnated curtains on Phlebotomus papatasi sandflies indoors at Khartoum, Sudan

Laboratory and field investigations were made in an endemic focus of cutaneous leishmaniasis in Khartoum State, Sudan, to evaluate the effects of permethrin-impregnated curtains on the human-biting activity, nocturnal activity and resting behaviour of the vector sandfly Phlebotomus papatasi (Diptera: Psychodidae) indoors. Laboratory bioassays showed that curtains impregnated with 0.5, 1.0 or 1.5 g/m2 permethrin all gave 100% mortality within 24h of exposure of P. papatasi for 3 min. Under natural field conditions, the biting activity indoors and the resting density of P. papatasi were significantly reduced (P<0.001 and P=0.036, respectively) in rooms provided with permethrin-impregnated curtains as compared to control rooms left without curtains or fitted with unimpregnated curtains. No significant difference was found between the numbers of nocturnally active P. papatasi collected in rooms provided with impregnated curtains and rooms left without curtains or provided with unimpregnated curtains (P=0.377). Evidently P. papatasi was not repelled by these doses of permethrin on curtains, but the survival rate of sandflies collected from test rooms provided with permethrin-impregnated curtains was significantly reduced (P=0.036). We conclude that use of permethrin-impregnated curtains may provide a good control method for P. papatasi and other endophilic and/or endophagic sandfly vectors of leishmaniasis.

The pathology of cutaneous leishmaniasis in the Sudan: a comparison with that in other geographical areas

The pathology of cutaneous leishmaniasis (CL) caused by Leishmania major zymodeme LON 1 in the Sudan was compared with that caused by L. major zymodeme LON 4 in Saudi Arabia and with that already described for L. tropica infections in Iran and for localized CL in the New World. The lesions were classified according to Ridley's five histological types. Most of the lesions in the Sudan and Saudi Arabia were of types B and C, characterized, respectively, by diffuse macrophage necrosis and focalized necrosis. B was the most common type in Nicaragua and Guyana whereas responses of types A (in which there are heavily parasitized macrophages without necrosis) and D (reactive tuberculoid) were the most frequent in Iran. The type-E response, which is similar to D but with virtual absence of plasma cells, was uncommon in all areas. The type-D reaction is a chronic relapsing disease when associated with L. tropica but not when associated with L. major. The major differences in the pathology of CL in different geographical areas most probably relate to differences in the Leishmania species involved. Minor differences, however, not only occur between patients from the same area but may also occur, with time, in the same patient. Detailed comparison between areas is therefore difficult; lesions on one patient may heal asynchronously and show different histological types at any point in time and rebiopsy from the same lesion during healing reveals changes from one histological type to another.

Cutaneous leishmaniasis: schedules for intralesional treatment with sodium stibogluconate

BACKGROUND

Various therapeutic modalities have been used for treating cutaneous leishmaniasis. Intralesional pentavalent antimonial injection is one of the effective therapeutic modalities. In this study, the efficacy of three different intralesional schedules with sodium stibogluconate have been investigated.

METHODS

Ninety-six patients with 129 lesions were entered into the study, all with confirmed diagnosis of cutaneous leishmaniasis. The lesions were treated with three different schedules, including daily, alternate day, and weekly interlesional injections of sodium stibogluconate. The clinical response was then compared to arrive at the most effective schedule.

RESULTS

The clinical responses (complete and partial cure) were 67%, 97%, and 91% for the daily, alternate-day, and weekly schedules, respectively. Lesions with either partial cure or failure of treatment were injected weekly with the same medication until complete cure had been achieved. The final overall success rate of complete cure was 99.2%.

CONCLUSIONS

Alternate day or weekly intralesional treatment of cutaneous leishmaniasis with sodium stibogluconate are more effective than daily treatments.

Evaluation of the polymerase chain reaction in the diagnosis of cutaneous leishmaniasis due to Leishmania major: a comparison with direct microscopy of smears and sections from lesions

We have compared the sensitivity of the polymerase chain reaction (PCR) as a diagnostic tool against conventional microscopical diagnostic techniques in patients with cutaneous leishmaniasis from the Sudan. Twenty-eight patients were diagnosed according to clinical criteria followed by microscopical examination of histological sections and slit or impression smears. The PCR had a sensitivity of 86% when used alone, and 93% when combined with Southern blotting. In contrast, microscopy of histological sections had a sensitivity of 76% and slit and impression smears of only 55% and 48%, respectively. The PCR should be considered as a valuable and sensitive diagnostic tool in the diagnosis of cutaneous leishmaniasis; it has the added advantage of identification of the species of Leishmania causing the lesion.

Diversity among Leishmania isolates from the Sudan: isoenzyme homogeneity of L. donovani versus heterogeneity of L. major

Leishmania isolates from patients in the Sudan suffering from either visceral or cutaneous leishmaniasis were characterized using a battery of 12 enzymes. Aspartate aminotransferase separated the L. donovani isolates into 2 distinct zymodemes, but the overall results showed no significant geographical variation among L. donovani isolates. In contrast, the isolates of L. major were polymorphic, exhibiting differences in nucleoside hydrolase, 6-phosphogluconate dehydrogenase, superoxide dismutase, esterase, mannose phosphate isomerase, and aspartate aminotransferase, resulting in the description of 4 new enzymatic variants.

Dichotomy of the T cell response to Leishmania antigens in patients suffering from cutaneous leishmaniasis; absence or scarcity of Th1 activity is associated with severe infections

The T cell response was studied in 25 patients suffering from cutaneous leishmaniasis caused by Leishmania major with severe (n = 10) and mild (n = 15) disease manifestations. Peripheral blood mononuclear cells (PBMC) from the patients were activated by sonicates of Leishmania promastigotes (LMP) and amastigotes (LDA), and the surface protease gp63. The proliferative responses to Leishmania antigens were lower in patients with severe disease than in patients with mild disease (P = 0.01-0.05), and such a difference was not observed in the response to purified protein derivative of tuberculin (PPD) or tetanus toxoid (TT). LMP-induced interferon-gamma (IFN-gamma) production was lower in patients with severe than in patients with mild disease (P < 0.05). When the IL-4 and IFN-gamma responses of each patient were considered, two response patterns were observed in the cultures activated by the Leishmania sonicates. One response pattern was characterized by high production of IFN-gamma without production of IL-4 (a Th1-like pattern), the other was characterized by low IFN-gamma levels which in most cases were associated with IL-4 production (not a Th1-like pattern). These patterns could not be distinguished when the cells from the same donors were stimulated by TT and PPD. The percentages of patients with a Th1-like response pattern after stimulation by LMP in patients with severe and mild disease manifestations were 30% and 80%, respectively. This difference was statistically significant (P = 0.034).

Antigen-presenting cells in human cutaneous leishmaniasis due to Leishmania major

In this study biopsies from skin lesions and draining lymph nodes of patients suffering from cutaneous leishmaniasis caused by Leishmania major were examined by immunohistochemistry, and by light and electron microscopy to identify the types of antigen-presenting cells (APC) and their location. APC, identified morphologically and by their expression of specific cell markers, included Langerhans cells, macrophages, follicular dendritic cells, and interdigitating reticulum cells of the paracortex of lymph nodes. These cells expressed MHC class II antigens and contained Leishmania antigen. Since some keratinocytes and endothelial cells also showed these characteristics, they may also act as APC. By examining tissue samples from skin lesions and draining lymph nodes it was possible to follow the probable route of trafficking of various inflammatory cells between the skin lesion and lymph nodes. Leishmania antigen containing Langerhans cells were found in the epidermis, dermis and the regional lymph nodes. We believe these cells translocate from the epidermis to the dermis, where they take up antigen and migrate to the paracortex of the regional lymph nodes. There they are intimately associated with cells of the paracortex, and could be involved in the generation of Leishmania-specific T memory cells. LFA-1-positive T cells of the CD45RO phenotype were found in the skin lesion. Venular endothelium in the skin lesions expressed intercellular adhesion molecule-1 (ICAM-1), which is the ligand for LFA-1. The migration of lymphocytes from the vascular lumen to the site of inflammation is possibly a result of the interaction of these two adhesion molecules.

Treatment of cutaneous leishmaniasis

The World Health Organization estimates that approximately 400,000 new cases of leishmaniasis occur worldwide each year. Cutaneous leishmaniasis is being encountered more frequently in the United States because of increasing travel and immigration from endemic areas. The indications for treatment and recommended treatment regimens reported in the infectious disease and dermatology literature vary widely. We examine both classic and newly developed therapeutic agents and modalities for cutaneous leishmaniasis. Proper therapy depends on species identification. New World leishmaniasis, in general, requires more aggressive therapy; parenteral antimonials are the drugs of choice. Physical modalities may suffice in most cases of Old World leishmaniasis because of its strong tendency toward spontaneous resolution.

Sporotrichoid cutaneous leishmaniasis due to Leishmania major of different zymodemes in the Sudan and Saudi Arabia: a comparative study

Sporotrichoid cutaneous leishmaniasis is due to dissemination of amastigotes via the lymphatics to the subcutaneous tissues. A comparison was made between the potential to disseminate by this route of 2 parasites of different zymodemes in Sudan and Saudi Arabia. In Sudan cutaneous leishmaniasis is caused by Leishmania major zymodeme LON-1, and in Saudi Arabia by L. major LON-4. Sporotrichoid leishmaniasis was significantly more common in Sudan, occurring in 23% of patients compared with 10% in Saudi Arabia. Lymph node involvement was slightly more prevalent in the Sudan. Clinical and pathological differences between subcutaneous nodules, particularly when they ulcerate, and multiple primary cutaneous lesions are described and treatment of localized and sporotrichoid leishmaniasis is discussed. The pathological features of the primary lesions in the Sudan and Saudi Arabia were similar.

The polymerase chain reaction can reveal the occurrence of naturally mixed infections with Leishmania parasites

On isolation and characterization of Leishmania parasites from Sudanese patients with visceral leishmaniasis (VL), four cases of mixed infections were found. Three of those cases were from the Eastern Sudan focus of VL. In one case the patient was found to be concomitantly infected with Leishmania donovani and Leishmania aethiopica, while the remaining three patients possessed mixed infections of Leishmania donovani and Leishmania major. Mixed infections were identified by PCR amplification of Leishmania kinetoplast DNA (kDNA) from parasites in culture or in original patient aspirate material and, additionally in the former cases by isoenzyme electrophoresis. In those cases where parasite culture was successful, PCR also demonstrated the rapidity with which one Leishmania species was eliminated from culture during continuous passage.

Studies on the leishmaniases in the Sudan. 3. Clinical and parasitological studies on visceral and mucosal leishmaniasis

The epidemiological, clinical and laboratory findings of 27 patients with visceral leishmaniasis (VL) and six with mucosal leishmaniasis (ML) in Sudan are described. The diagnosis was confirmed by the demonstration of amastigotes in bone-marrow in 20 cases with VL (80%) and impression smears in 2 cases with ML. The enzyme-linked immunosorbent assay and direct agglutination test were positive in all the sera tested. The leishmanin test was positive in all patients with ML, the diameter of the reaction ranging from 18 to 28 mm (mean 23 mm). Only one isolate (from a patient with VL) grew sufficiently well in culture to be typed and this was characterized by isoenzyme electrophoresis as Leishmania donovani zymodeme LON-46. The possibility that the ML isolate could have been L. major zymodeme LON-1 is discussed. The importance of further research to isolate and identify by biochemical procedures a more representative range of isolates of Leishmania from different clinical types in the Sudan, in order to elucidate questions such as the relationship between the vectors and possible animal reservoirs, is emphasized.