Signs Of Leishmaniasis Research Articles

Microscopic and molecular evidence in support of rodent as a reservoir for dissemination of Leishmaniasis.

Leishmaniasis is a worldwide public health problem and vector-borne disease. It is caused by a diverse group of protozoan parasites that belong to the genus Leishmania and transmitted to humans through a bite of an infected female sand fly. Leishmaniasis has attained epidemic proportion in Khyber Pakhtunkhwa and raises serious concern over its management. The present research work was conducted in cutaneous leishmaniasis (CL) prevalent village named Surgul of district Kohat, Khyber Pakhtunkhwa with a focus to investigate whether rodent can act as a source for dissemination of leishmanial species or not. In this context, rodent samples were analyzed via morphological and molecular approaches to unveil prevalence of CL. It was reported that 12.5% of samples were positive for signs of leishmaniasis through microscopy and 18.75% through polymerase chain reaction (PCR). Supporting the findings further, the color character of rodents was also taken into consideration, which shows that light dark colored rodents were more infected (13.3%) compared to brown colored rodents (11.43%). Based on our findings, we speculate that small rodents are a possible reservoir of various leishmanial parasites and play a significant role in zoonosis and maintenance of their species.

Visceral leishmaniasis presenting with paroxysmal cold haemoglobinuria.

Paroxysmal cold haemoglobinuria, first described by Donath and Landsteiner in 19041,2, is a rare autoimmune haemolytic anaemia, defined by the presence of an IgG biphasic haemolysin. It is generally considered an acute self-limited anaemia caused by an IgG biphasic auto-anti-P antibody (Donath-Landsteiner [DL]-haemolysin). The autoantibody is called biphasic because it sensitises red cells at 0–4 °C and causes complement-mediated haemolysis at higher temperatures. The generally reported incidence ranges from 1.6 to 5.1% in childhood haemolytic anaemia3, although an incidence of as high as 32% was found in one small series4. Most of the data are probably too old to reflect the true incidence at present; the haemolysis caused by DL antibody could be underestimated since proper testing is rarely performed. In the past years, a positive DL test has characterized a chronic disorder known as cold haemoglobinuria, usually secondary to syphilis. Currently, most cases of DL-haemolytic anaemia occur as acute transient episodes in children and young adults after and/or concomitant with a variety of viral and bacterial infections including measles, mumps, chickenpox, cytomegalovirus, Epstein-Barr virus, adenovirus type 2, influenza A, Klebsiella spp., Haemophilus influenzae, Mycoplasma and E. Coli infections, or as a complication of vaccinations2–6. We report here the case of a very young Caucasian child with acute haemolytic anaemia due to a DL red cell autoantibody, as the first sign of leishmaniasis.

Is the Dog a Possible Reservoir for Cutaneous Leishmaniasis in Suriname?

Cutaneous leishmaniasis (CL) is an emerging disease in Suriname, with at least 200 cases per year. Little is known about the biology of CL in the country. The most important parasite species is Leishmania Viannia guyanensis, but possible vectors and reservoirs are hardly incriminated. In the present study, it was investigated whether the dog could possibly be a zoonotic reservoir for the disease in Suriname. Forty-seven dogs were examined for overt clinical signs of leishmaniasis, and blood samples were collected on filter paper for serology (direct agglutination test) and molecular biology (by polymerase chain reaction). Three dogs had clinical signs that could be compatible with canine cutaneous leishmaniosis: dermatitis (two) or nasal lesion (one). Two dogs were seropositive with DAT (titre > 1 : 1600), and three animals had a borderline titre (1 : 800). All other animals (n = 42) were DAT negative. PCR analysis found Leishmania DNA equivalent to 1 parasite per mL in only one dog at a first round of analysis, but this animal was negative after retesting. The clinical, serological, and molecular data show some preliminary lines of evidence that canine leishmaniosis is present in Suriname, but further studies are needed to incriminate the reservoir, including a possible sylvatic cycle.

Canine leishmaniasis: clinical, parasitological and entomological follow-up after chemotherapy.

Six naturally infected dogs [two with no signs of leishmaniasis ('asymptomatic'), two with a few signs ('oligosymptomatic') and two with many signs ('polysymptomatic')] were studied before and after chemotherapy. Another two, non-infected dogs were kept as controls. The dogs were studied clinically, haematologically and parasitologically five times over 11 months and their infectivity to sandflies was evaluated before and after the treatment. The 'asymptomatic' dogs were as infective to sandflies as the 'symptomatic' before treatment but all dogs were un-infective for at least a few months following chemotherapy. Treatment led to a temporary improvement in the clinical and biochemical condition of most of the dogs, the symptomatic dogs becoming asymptomatic, but parasitological cure was uncommon after 10 months' follow-up. There was often no correlation between clinical condition, parasitological condition and infectivity to sandflies. Some dogs from both the 'asymptomatic' and 'symptomatic' groups became infective to sandflies several months post-treatment.

Decreased sensitivity to meglumine antimoniate (Glucantime) of Leishmania infantum isolated from dogs after several courses of drug treatment.

Although unresponsiveness to antimonial drugs in human leishmaniasis appears to be increasing, resistance to antimony in Leishmania is not well documented. Treatment of leishmaniasis in dogs, the domestic reservoir of L. infantum, with meglumine antimoniate (Glucantime) is a common practice in many Mediterranean countries. The dogs, however, remain highly infective to the phlebotomine vectors, even after several courses of treatment. A study was therefore carried out to test the comparative susceptibility to meglumine antimoniate of L. infantum stocks isolated from four naturally-infected dogs, before (BT) and after treatment (AT) with three to six courses of the drug, and used to infect Balb/c mice. Significant differences in suppression between the BT and AT stocks were observed in the infected mice when they were given the drug at a rate of 0.01-10 mg kg-1 day-1 for five days. Each AT stock was between eight and 41 times more resistant to meglumine antimoniate than the BT stock from the same dog, in terms of the ratios of the AT ED50 values to the corresponding BT values, which were calculated as indices of resistance. This result underlines the futility and danger of repeated antimonial treatments of dogs with signs of leishmaniasis, as these may produce a permanent reservoir of parasites unsusceptible to the drugs in human clinical use.