INTRODUCTION: Various methods are used for the diagnosis of visceral leishmaniasis (VL), such as microscopic examination, culture and inoculation of laboratory animals; however, serological assays are commonly used for the detection of antibodies in serum samples with a wide range of specificity and sensitivity. METHODS: The purpose of this study was to compare three serological methods, including rA2-ELISA, the recombinant KE16 (rKE16) dipstick test and the direct agglutination test (DAT), for the detection of antibodies against VL antigens. The assays utilized 350 statistically based random serum samples from domestic dogs with clinical symptoms as well as samples from asymptomatic and healthy dogs from rural and urban areas of the Meshkinshahr district, northwestern Iran. RESULTS: Samples were assessed, and the following positive rates were obtained: 11.5% by rKE16, 26.9% by DAT and 49.8% by ELISA. The sensitivity among symptomatic dogs was 32.4% with rKE16, 100% with DAT and 52.9% with ELISA. Conversely, rA2-ELISA was less specific for asymptomatic dogs, at 46.5%, compared with DAT, at 88.9%. CONCLUSIONS : This study recommends rA2-ELISA as a parallel assay combined with DAT to detect VL infection among dogs. Further evaluations should be performed to develop an inexpensive and reliable serologic test for the detection of Leishmania infantum among infected dogs.

Cutaneous leishmaniasis (CL) is a widespread tropical infection which has a high incidence rate in Iran. Leishmania tropica, the causative agent of anthroponotic cutaneous leishmaniasis (ACL), and Leishmania major, which causes zoonotic cutaneous leishmaniasis (ZCL), are endemic in various parts of Iran with a high incidence rate. The aim of this study was to evaluate the reappraisal of the diagnosis and epidemiology of CL in Iran, by different clinical, parasitological and molecular assays among patients suspected of CL referred to the Department of Parasitology, at the Pasteur Institute of Iran during 2006-2009. Two hundred samples from patients with ulcerative skin lesions were collected, clinical analyses were applied, data questionnaire was completed and samples were examined for CL by using both direct microscopic and culture methods. Moreover, PCR assay was applied for detection of Leishmania species in CL isolates resulting from parasitological assay. Clinical observation revealed that the majority (58%) of lesions was single; double lesions were observed in 22% of patients, and only 20% of CL had multiple lesions. Out of 200 patients, Leishman body was observed in 77 samples (38.5%) by direct smear and 40% by cultivation assay. Most patients (21.3%) had a travel history to the Isfahan province, one of the most important endemic areas of CL located in center of Iran. PCR assay by kDNA indicated 32 and 18 out of 50 isolates respectively had similar patterns with standard L. major and L. tropica. In conclusion, clinical manifestations and an appropriate diagnostic assay with a parallel molecular characterization of CL may lead to a screening evaluation of disease, prognosis, treatment and control strategies.

INTRODUCTION: Severe cognitive impairment follows thyroid hormone deficiency during the neonatal period. The role of nitric oxide (NO) in learning and memory has been widely investigated. METHODS: This study aimed to investigate the effect of hypothyroidism during neonatal and juvenile periods on NO metabolites in the hippocampi of rats and on learning and memory. Animals were divided into two groups and treated for 60 days from the first day of lactation. The control group received regular water, whereas animals in a separate group were given water supplemented with 0.03% methimazole to induce hypothyroidism. Male offspring were selected and tested in the Morris water maze. Samples of blood were collected to measure the metabolites of NO, NO2, NO3 and thyroxine. The animals were then sacrificed, and their hippocampi were removed to measure the tissue concentrations of NO2 and NO3. DISCUSSION: Compared to the control group's offspring, serum thyroxine levels in the methimazole group's offspring were significantly lower (P<0.01). In addition, the swim distance and time latency were significantly higher in the methimazole group (P<0.001), and the time spent by this group in the target quadrant (Q1) during the probe trial was significantly lower (P<0.001). There was no significant difference in the plasma levels of NO metabolites between the two groups; however, significantly higher NO metabolite levels in the hippocampi of the methimazole group were observed compared to controls (P<0.05). CONCLUSION: These results suggest that the increased NO level in the hippocampus may play a role in the learning and memory deficits observed in childhood hypothyroidism; however, the precise underlying mechanism(s) remains to be elucidated.

Nitric oxide (NO) is a potent mediator with diverse roles in regulating cellular functions and signaling pathways. The NO synthase (NOS) enzyme family consists of three major isoforms, which convey variety of messages between cells, including signals for vasorelaxation, neurotransmission and cytotoxicity. This family of enzymes are generally classified as neuronal NOS (nNOS), endothelial NOS (eNOS) and inducible NOS (iNOS). Increased levels of NO are induced from iNOS during infection; while eNOS and nNOS may be produced at the baseline in normal conditions. An association of some key cytokines appears to be essential for NOS gene regulation in the immunity of infections. Accumulating evidence indicates that parasitic diseases are commonly associated with elevated production of NO. NO plays a role in the immunoregulation and it is implicated in the host non-specific defence in a variety of infections. Nevertheless, the functional role of NO and NOS isoforms in the immune responses of host against the majority of parasites is still highly controversial. In the present review, the role of parasitic infections will be discussed in the controversy related to the NO production and iNOS gene expression in different parasites and a variety of experimental models.

Several enzymes that contribute to immune system responses require zinc and copper as trace elements for their activity. We examined zinc and copper levels in two susceptible Balb/c mouse lines and resistant C57bl/6 mice infected with Leishmania major MRHO/IR/75/ER, a prevalent strain that causes cutaneous leishmaniasis in Iran. Serum Zn and Cu were determined by flame atomic absorption spectrophotometry. Higher Cu levels were found in infected C57bl/6 mice and higher Zn levels were found in infected Balb/c mice. Also, Cu/Zn ratios were increased in both the Balb/c and the C57bl/6 mice. We conclude that concentrations of essential trace elements vary during cutaneous leishmaniasis infection and that this variation is associated with susceptibility/resistance to Leishmania major in Balb/c and C57bl/6 mice. We detected Zn deficiency in the plasma of infected Balb/c mice; possibly, therapeutic administration of Zn would be useful for treating this form of leishmaniasis. Increases in Cu level might increase resistance to leishmaniasis. Based on our findings, the Cu/Zn ratio could be a useful marker for the pathophysiology of leishmaniasis.

In addition to numerous immune factors, C-reactive protein (CRP) and nitric oxide (NO) are believed to be molecules of malaria immunopathology. The objective of this study was to detect CRP and NO inductions by agglutination latex test and Griess microassay respectively in both control and malaria groups from endemic areas of Iran, including Southeastern (SE) (Sistan & Balouchestan, Hormozgan, Kerman) and Northwestern (NW) provinces (Ardabil). The results indicated that CRP and NO are produced in all malaria endemic areas of Iran. In addition, more CRP and NO positive cases were observed amongst malaria patients in comparison with those in control group. A variable co-association of CRP/NO production were detected between control and malaria groups, which depended upon the malaria endemic areas and the type of plasmodia infection. The percentage of CRP/NO positive cases was observed to be lower in NW compare to SE region, which may be due to the different type of plasmodium in the NW (Plasmodium vivax) with SE area (P. vivax, Plasmodium falciparum, mixed infection). The fluctuations in CRP/NO induction may be consistent with genetic background of patients. Although, CRP/NO may play important role in malaria, their actual function and interaction in clinical forms of disease remains unclear.

Nitric oxide (NO) is thought to be an important mediator and critical signaling molecule for malaria immunopathology; it is also a target for therapy and for vaccine. Inducible nitric oxide synthase (iNOS) is synthesized by a number of cell types under inflammatory conditions. The most relevant known triggers for its expression are endotoxins and cytokines. To date, there have been conflicting reports concerning the clinical significance of NO in malaria. Some researchers have proposed that NO contributes to the development of severe and complicated malaria, while others have argued that NO has a protective role. Infection with parasites resistant to the microbicidal action of NO may result in high levels of NO being generated, which could then damage the host, instead of controlling parasitemia. Consequently, the host-parasite interaction is a determining factor for whether the parasite is capable of stimulating NO production; the role of NO in resistance to malaria appears to be strain specific. It is known that NO and/or its related molecules are involved in malaria, but their involvement is not independent of other immune events. NO is an important, but possibly not an essential contributor to the control of acute-phase malaria infection. The protective immune responses against malaria parasite are multifactorial; however, they necessarily involve final effector molecules, including NO, iNOS and RNI.