Mean Parasite Load Research Articles

GC–MS Profiling and Antimalarial Activity of Khaya grandifoliola on Plasmodium berghei–infected mice

ABSTRACTThis study evaluated the antiplasmodial activity and chemical constituents of ethanolic leaf extract of Khaya grandifoliola on mice infected with Plasmodium berghei. Twenty-five mice of both sexes (~30–40 g) were divided into five groups of five mice each. Group 1 (normal control) was untreated and uninfected. Groups 2–5 were intraperitoneally inoculated with 2.5 × 107 P. berghei, while group 2 (disease control [DC]) was untreated-infected group, group 3 (standard drug) received a standard drug, artesunate (50 mg kg−1 b.w.) for 4 consecutive days; groups 4 (LEKG50) and 5 (LEKG100) received ethanolic leaf extracts of K. grandifoliola at 50 mg kg−1 b.w. and 100 mg kg−1 b.w., respectively, after establishment of infection. The LD50 was 4,207.5 mg kg−1 b.w. The results showed a reduction in the mean parasite load of LEKG50 and LEKG100 when compared with DC at day 6 postinfection and beyond. Both LEKG50 and LEKG100 recovered in packed cell volume after an initial drop. There were variable changes in the level of lymphocytes, monocytes, eosinophils, and neutrophils in both LEKG50 and LEKG100 throughout the study period. Sixteen constituents were identified by gas chromatography/mass spectrometry analysis, and oleic acid (33.83%) was most prominent.

Detection of Leishmania infantum DNA in phlebotomine sand flies from an area where canine leishmaniosis is endemic in southern Italy

Phlebotomine sand flies (Diptera, Psychodidae) are vectors of Leishmania spp., among which Leishmania infantum is recognized as the main agent of human and canine leishmaniosis (CanL) in the Mediterranean area. In this study, females of Phlebotomus spp. (P. perniciosus, P. neglectus and P. papatasi) and Sergentomyia minuta were collected in a dog shelter of southern Italy, where CanL is endemic, and examined for Leishmania DNA. In total, 32 out of 56 of Phlebotomus spp. insects (57.1%) were found positive for L. infantum DNA by quantitative PCR (qPCR), with a mean parasite load of 1.9 × 103 promastigotes/ml among 23 positive P. perniciosus and 2.1 × 103 promastigotes/ml among five positive P. neglectus. Four P. papatasi, a species known to be refractory to L. infantum development, were also found positive. Among 216 S. minuta specimens examined, 25 (11.6%) scored positive for Leishmania tarentolae by conventional nested PCR; two (16.7%) of them were also positive for lizard blood, which is in agreement with the feeding preference of this phlebotomine species. Nine S. minuta (4.2%) were positive for L. infantum by qPCR, with a mean parasite load of 1.62 × 102 promastigotes/ml. The detection of L. infantum DNA in S. minuta may suggest that this species could acquire the protozoan, occasionally feeding on infected dogs. Further investigations need to clarify the potential role that S. minuta may have in the transmission of L. infantum to receptive mammal hosts.

Use of a real-time PCR to explore the intensity of Plasmodium spp. infections in native, endemic and introduced New Zealand birds.

Avian malaria, caused by Plasmodium spp., is an emerging disease in New Zealand (NZ). To detect Plasmodium spp. infection and quantify parasite load in NZ birds, a real-time polymerase chain reaction (PCR) (qPCR) protocol was used and compared with a nested PCR (nPCR) assay. A total of 202 blood samples from 14 bird species with known nPCR results were tested. The qPCR prevalences for introduced, native and endemic species groups were 70, 11 and 21%, respectively, with a sensitivity and specificity of 96·7 and 98%, respectively, for the qPCR, while a sensitivity and specificity of 80·9 and 85·4% were determined for the nPCR. The qPCR appeared to be more sensitive in detecting lower levels of parasitaemia. The mean parasite load was significantly higher in introduced bird species (2245 parasites per 10 000 erythrocytes) compared with endemic species (31·5 parasites per 10 000 erythrocytes). In NZ robins (Petroica longipes), a significantly lower packed cell volume was found in birds that were positive for Plasmodium spp. compared with birds that were negative. Our data suggest that introduced bird species, such as blackbirds (Turdus merula), have a higher tolerance for circulating parasite stages of Plasmodium spp., indicating that introduced species are an important reservoir of avian malaria due to a high infection prevalence and parasite load.

When can we infer mechanism from parasite aggregation? A constraint-based approach to disease ecology.

Few hosts have many parasites while many hosts have few parasites. This axiom of macroparasite aggregation is so pervasive it is considered a general law in disease ecology, with important implications for the dynamics of host-parasite systems. Because of these dynamical implications, a significant amount of work has explored both the various mechanisms leading to parasite aggregation patterns and how to infer mechanism from these patterns. However, as many disease mechanisms can produce similar aggregation patterns, it is not clear whether aggregation itself provides any additional information about mechanism. Here we apply a "constraint-based" approach developed in macroecology that allows us to explore whether parasite aggregation contains any additional information beyond what is provided by mean parasite load. We tested two constraint-based null models, both of which were constrained on the total number of parasites P and hosts H found in a sample, using data from 842 observed amphibian host-trematode parasite distributions. We found that constraint-based models captured ~85% of the observed variation in host-parasite distributions, suggesting that the constraints P and H contain much of the information about the shape of the host-parasite distribution. However, we also found that extending the constraint-based null models can identify the potential role of known aggregating mechanisms (such as host heterogeneity) and disaggregating mechanisms (such as parasite-induced host mortality) in constraining host-parasite distributions. Thus, by providing robust null models, constraint-based approaches can help guide investigations aimed at detecting biological processes that directly affect parasite aggregation above and beyond those that indirectly affect aggregation through P and H.

Laboratory Diagnosis of Malaria: Comparison of Manual and Automated Diagnostic Tests

Malaria is the second most prevalent disease in Pakistan resulting in ~30,000 annual deaths. In endemic countries like Pakistan precise and timely diagnosis of malaria is imperative to overcome the associated risks of fatal outcomes. Malarial parasite was screened in 128 malaria suspected patients and 150 healthy controls, by species-specific PCR, microscopy of blood smears, hemoanalyzer Sysmex XE-2100, and rapid test devices (First Response Malaria® and ICT Malaria Combo®). The microscopy detected MP in 126 samples (parasite load/µl 386–53712/µl); 71.094% were infected with Plasmodium vivax and 14.844% with P. falciparum while 14.062% had mixed P. vivax and P. falciparum infection. The mean parasite load for P. vivax and P. falciparum was 14496/µl and 24410/µl, respectively. The abnormal scattergrams of DIFF, WBC/ Baso, IMI channel, and RET-EXT on Sysmex XE-2100 supported 99.2% parasite detection, whereas only 93% of confirmed malaria cases were detected by both rapid tests. About 127 samples were positive by PCR. Since Sysmex XE-2100 automatically detected the presence of malarial parasite with high sensitivity, it can be a good option for presumptive diagnosis in endemic areas. Microscopy remains the gold standard to confirm MP in suspected patients. Rapid diagnostic tests have acceptable sensitivity and specificity.

Effect of deworming regimen on helminths and growth performances in growing Ganjam goats

Present work was carried out in the Ganjam Field Unit of AICRP on Goat improvement, Odisha to study the effect of deworming regimen on helminths and growth performances in growing Ganjam goats. It was found that deworming by using Ivermectin and Fenbendazole or Oxyclozanide and Levamisole preparation has got a significant effect on Ganjam kids with respect to body weight gain, haemoglobin, serum total protein, albumin and parasitic load. The effect of Ivermectin and Fenbendazole combination was found to be superior over Oxyclozanide and Levamisole combination on growth rate, helminthic infestation in terms of parasitic load and FECRT value. A negative correlation was observed between Hb% and PCV% with the mean parasitic load. Effect of deworming regimen was found to be non-significant at 2 or 3 months intervals using different anthelmintics with respect to parasitic load and growth performance. The deworming against helminths at an interval of 3 months is equally effective, economic and labour saving compared to 2 months.

EFECTO DEL USO DE MOXIDECTINA SOBRE LA CARGA PARASITARIA Y ERITROGRAMA DE CORDEROS EN TRES ESTABLECIMIENTOS UBICADOS EN EL DISTRITO DE HERNANDARIAS, PARAGUAY

In order to evaluate effect on the parasite load and erythrogram in lambs, 15 sheep were used in three establishments in Hernandaria District, Paraguay. Parasite load and larvae cultivation were determined in feces; hematocrit, hemoglobin, erythrocytes, erythrocyte indices and total protein were determined in blood. These tests were performed on three successive times, called take 0 (day 0) pretreatment, take 1 (day 15) after treatment, take 2 (day 30) after treatment. The following results were obtained: for parasite load the average was: day 0 = 1,540 EPG, day 15 = 113 EPG, day 30 = 40 EPG. 80% of the parasites belonged to the genus Haemonchus spp. The mean parasite load in lambs treated with moxidectin decreased significantly, 15 and 30 days after treatment. Effectiveness results of moxidectin were 91.4% on day 15 and 97% on day 30. Erythrogram improved, hematocrit, hemoglobin and red blood cell count increased to 30 days post treatment with statistically significant differences being (p = 0.004) (p <0.0001) and (p = 0.0001), respectively. The present study showed highly significant negative correlations for the parasite load with hemoglobin (r = -0.53, p = 0.0002), hematocrit (r = -0.42, p = 0.004) and MCHC (r = -0.34, p = 0.02), but not with the load parasite and erythrocyte count, where the results were not significant (r = -0.26, p = 0.09).

New records of species of Saemundssonia (Insecta: Phthiraptera: Philopteridae) infesting breeding terns in the Arabian Peninsula, with notes on their phylogeny and ecology.

Six species of terns, which breed on the Arabian Peninsula, were examined for head chewing lice of the genus Saemundssonia in four different islands around the coasts of Saudi Arabia, both in the Red Sea and in the Arabian Gulf. Four louse species were collected: Saemundssonia laticaudata, Saemundssonia melanocephalus, Saemundssonia meridiana and Saemundssonia sternae, of which three are recorded for the first time from this region. Also, we record three new host-louse associations for the world-Saemundssonia laticaudata and Saemundssonia sternae from white-cheeked terns and Saemundssonia melanocephalus from Saunders's terns-including a host-switch event of Saemundssonia laticaudata on white-cheeked terns in the Karan Island population. Gene bank data for the COI gene from seven species of Saemundssonia that infest marine birds were used to propose evolutionary trees using two different statistical methods: maximum parsimony (MP) and neighbour joining (NJ). The result indicated that the tree which was produced by NJ is likely to be more accurate as it appeared more compatible with hosts' phylogeny. The trees indicate relationships between tern Saemundssonia and congeneric species from other marine birds, especially from gulls. An ANOVA was also conducted to test the mean parasite load for each tern species studied, and results indicate that there is a relation between louse loads and colonization behaviour of the hosts. Data from lice examined and illustrations of lice and their hosts are also included.

Prevalence of Soil Transmitted Helminthes (STH) Infection among Children Aged 2-17 Years in Urban and Rural Areas of Dhaka District in Bangladesh

A multi-staged cross sectional study was conducted among children aged 2 -17 years to assess the level of soil transmitted helminthes (ST H) infections and its relation to socio-demographic characteristics among them. Two thousand children were randomly selected from two rural and four different communities of urban areas of Dhaka district since November 2009 to June 2010. Four different communities classified as higher, medium, poorer and slum/ low socio-economic groups from urban areas were selected on the basis of their place of residence with different socio-economic status. Urban study subjects were again sub grouped into upper (higher and medium socio-economic) and lower (poorer and slum/low socio-economic) classes. Stool specimens of the respondents were collected and tested at the Parasitology department of I E DCR , using the Kato-katz faecal technique for identification of helminthes eggs following their morphology (A. lumbricoides, Ttrichiura, and A. duodenale), and larval stage (S. stercoralis). About 32.15% study population harbored at least one of the four helminthes species. Baseline prevalence of infections and mean parasite loads for Ascaris lumbricoides were 40.61% and 600.80 e/g, for Trichuris trichiura 30.42% and 206.11e/g, and for A. duodenale 6.80% and 78.75 e/g. Three children (0.49%) were positive for Strongyloides stercoralis. Single infection of 78.32 % and double infection of 21.68 % were recorded. Single infection of A. lumbricoides (40.61%) and T trichiura (30.42%) and double infection of A. lumbricoides - T trichiura (18.61%) were more prevalent. T he prevalence of ST H infection was 25.47 % and 38.68 % for rural and urban areas respectively (P&lt;.001). Among urban study subjects, the distribution of ST H infection was 0.0 % in the higher (living in higher socioeconomic areas) (only 3 samples could be collected), 26.75 % in medium (living in medium socio-economic areas), 45.95 % in poorer and 50.54 % in slum/low socio-economic groups. Significantly higher number of ST H infection was observed among lower than that in upper socio-economic classes (P &lt;.001). These results suggest that ST H infections remain a serious health problem among children in Bangladesh and need appropriate prevention and control measures.DOI: http://dx.doi.org/10.3329/bjmm.v5i2.16933 Bangladesh J Med Microbiol 2011; 05 (02): 16-22

Quantification of Leishmania infantumDNA in the bone marrow, lymph node and spleen of dogs

The aim of the present study was to quantify the parasite load of Leishmania infantum in dogs using real-time PCR (qPCR). Bone marrow, lymph node and spleen samples were taken from 24 dogs serologically positive for L. infantum that had been put down by the official epidemiological surveillance service. According to the clinical signs the dogs were classified as asymptomatic or symptomatic. After DNA extraction, the samples were subjected to qPCR to detect and quantify L. infantum DNA. Out of the 24 dogs, 12.5% (3/24) were classified as asymptomatic and 87.5% (21/24) as symptomatic. Real-time PCR detected L. infantum DNA in all the animals, in at least one biological sample. In particular, 100% of bone marrow and lymph node scored positive, whereas in spleen, the presence of DNA was detected in 95.9% (23/24). In addition, out of 24 animals, 15 were microscopically positive to amastigote forms of L. infantum in bone marrow. No statistical significant difference was found in the overall mean quantity of DNA among the different biological samples (P = 0.518). Considering each organ separately, there was 100% positivity in bone marrow and lymph nodes, while among the spleen samples, 95.9% (23/24) were positive. Regarding the different clinical groups, the overall mean parasite load varied significantly (P = 0.022). According to the results obtained, it was not possible determine which biological sample was most suitable tissue for the diagnosis, based only on the parasite load. Therefore, other characteristics such as convenience and easily of obtaining samples should be taken into consideration.

Do blackcaps win host-ectoparasite arms race by building lacy nests and shortening nestling period?

We studied the effect of ectoparasitism by hematophagous larvae of the blow fly of the genus Protocalliphora on nestling blackcaps Sylvia atricapilla in southeast Poland. Approximately 81% of blackcap nests left by nestlings contained Protocalliphora larvae; however, mean parasite load was only 1.8 larvae per nestling. Nestling mass and tarsus length measured just before fledging did not differ significantly with parasite load. This finding might have resulted from several factors. First, the number of larvae per nestling was very low, which may be connected with the structure of blackcap nests. Second, the time of exposure of nestlings to parasitic larvae in the studied species is relatively short as fledglings are able to leave a nest when they are 9 days old. The combination of the open lacework structure of blackcap nest and a very short nestling period may constitute an evolutionary adaptation that enables blackcap nestlings to escape the cost of Protocalliphora parasitism.

Prevalence and infection intensity of sea lice (Lepeophtheirus salmonis) on Atlantic salmon (Salmo salar) host is reduced by the non-host compound 2-aminoacetophenone

Chemical cues, or semiochemicals, are used by parasitic sea lice (Lepeophtheirus salmonis) not only in the identification and location of host salmonid fish, but also in the avoidance of unsuitable fish hosts. In this study, an identified non-host semiochemical, 2-aminoacetophenone (2-AA), isolated from turbot (Scophthalmus maximus) was used in the field to reduce sea lice prevalence and infective capability. Field trials were conducted at an experimental fish farm in north-west Scotland, in order to determine the effect of 2-AA on L. salmonis abundance on Atlantic salmon (Salmo salar) hosts. Salmon smolts were maintained in small pens fitted with a polymer ribbon impregnated with 2-AA. The ribbon was designed to release 2-AA into seawater over an extended period. Three separate trials were undertaken in June–July and November–December 2011, over periods lasting 39, 11 and 11days, when the fish were exposed to natural sea lice challenges. Prevalence and parasite loads observed were consistently lower on fish where the non-host cue was released. Prevalence ranged from 24–60% fish with lice in controls, to 12–35% fish in the 2-AA treatments, representing effective reductions of 43–62%. Mean parasite load ranged from 0.30–1.19 lice/fish in controls to 0.12–0.52 lice/fish in 2-AA treatments, representing effective reductions of 43–56%. The principle of interfering with ectoparasitism in fish by means of non-host semiochemical cues is demonstrated. Further investigations are required, in order to determine the potential value of semiochemical application as an effective pest management tool in the salmon farming industry.

Detection and quantification of Leishmania braziliensis in ectoparasites from dogs

American cutaneous leishmaniosis (ACL) is a disease caused by different species of Leishmania protozoa, Leishmania braziliensis being the main species found in Brail. In this study, two rural areas in Pernambuco, northeastern Brazil, where ACL is endemic, were selected. Genomic DNA was extracted from canine ectoparasites (ticks, fleas, and lice) and tested using a conventional PCR and a quantitative real time PCR. A total of 117 ectoparasites were collected, being 50 (42.74%) of them positive for L. braziliensis (in at least one PCR protocol), with a mean parasite load of 14.14fg/μL. Furthermore, 46 (92.00%) positive ectoparasites were collected from positive dogs and 4 (8.00%) from negative ones. This study reports the detection of L. braziliensis DNA in ectoparasites, but does not prove their vector competence. Certainly, experimental transmission studies are necessary to assess their role, if any, in the transmission of Leishmania parasites to dogs.

A New Model of Progressive Visceral Leishmaniasis in Hamsters by Natural Transmission via Bites of Vector Sand Flies

Visceral leishmaniasis (VL) is transmitted by sand flies. Protection of needle-challenged vaccinated mice was abrogated in vector-initiated cutaneous leishmaniasis, highlighting the importance of developing natural transmission models for VL. We used Lutzomyia longipalpis to transmit Leishmania infantum or Leishmania donovani to hamsters. Vector-initiated infections were monitored and compared with intracardiac infections. Body weights were recorded weekly. Organ parasite loads and parasite pick-up by flies were assessed in sick hamsters. Vector-transmitted L. infantum and L. donovani caused ≥5-fold increase in spleen weight compared with uninfected organs and had geometric mean parasite loads (GMPL) comparable to intracardiac inoculation of 10(7)-10(8) parasites, although vector-initiated disease progression was slower and weight loss was greater. Only vector-initiated L. infantum infections caused cutaneous lesions at transmission and distal sites. Importantly, 45.6%, 50.0%, and 33.3% of sand flies feeding on ear, mouth, and testicular lesions, respectively, were parasite-positive. Successful transmission was associated with a high mean percent of metacyclics (66%-82%) rather than total GMPL (2.0 × 10(4)-8.0 × 10(4)) per midgut. This model provides an improved platform to study initial immune events at the bite site, parasite tropism, and pathogenesis and to test drugs and vaccines against naturally acquired VL.

Detection of Leishmania infantum in animals and their ectoparasites by conventional PCR and real time PCR

Visceral leishmaniosis (VL) is a parasitic disease caused by Leishmania infantum, which is primarily transmitted by phlebotomine sandflies. However, there has been much speculation on the role of other arthropods in the transmission of VL. Thus, the aim of this study was to assess the presence of L. infantum in cats, dogs and their ectoparasites in a VL-endemic area in northeastern Brazil. DNA was extracted from blood samples and ectoparasites, tested by conventional PCR (cPCR) and quantitative real time PCR (qPCR) targeting the L. infantum kinetoplast DNA. A total of 280 blood samples (from five cats and 275 dogs) and 117 ectoparasites from dogs were collected. Animals were apparently healthy and not previously tested by serological or molecular diagnostic methods. Overall, 213 (76.1 %) animals and 51 (43.6 %) ectoparasites were positive to L. infantum, with mean parasite loads of 795.2, 31.9 and 9.1 fg in dogs, cats and ectoparasites, respectively. Concerning the positivity between dogs and their ectoparasites, 32 (15.3 %) positive dogs were parasitized by positive ectoparasites. The overall concordance between the PCR protocols used was 59.2 %, with qPCR being more efficient than cPCR; 34.1 % of all positive samples were exclusively positive by qPCR. The high number of positive animals and ectoparasites also indicates that they could serve as sentinels or indicators of the circulation of L. infantum in risk areas.

Study of parasite kinetics with antileishmanial drugs using real-time quantitative PCR in Indian visceral leishmaniasis

This study describes parasite kinetics in the blood of visceral leishmaniasis patients treated with liposomal amphotericin B (L-AmB) or a preformed fat emulsion of amphotericin B (ApL) using real-time quantitative PCR (qPCR). Forty-six patients were treated with a single dose (15 mg/kg of body weight) of either L-AmB (n = 13) or ApL (n = 33). qPCR was used to estimate parasite kinetics by detection of Leishmania donovani DNA using kinetoplast DNA-specific primers in peripheral blood samples using an absolute quantification method. The mean parasite load decreased from baseline (day 0) values of 894.07 and 980.48 to 71.72 and 211.52 parasite genomes/mL at day 7 in L-AmB and ApL groups, respectively, and at day 30 these further declined to 8.30 and 133.98 parasite genomes/mL, respectively. At day 30 post-treatment evaluation, the decline in parasite load was significantly greater (P = 0.024) with L-AmB compared with ApL. Four of 33 patients in the ApL group failed treatment (1 primary failure and 3 relapses) with the presence of parasites, whereas all patients in the L-AmB group were cured at 6 month follow-up. qPCR can be a tool to measure parasite dynamics accurately and provide a marker to measure the efficacy of various drugs. It can be used as a test of cure, allowing us to do away with invasive and risky methods such as splenic or bone marrow aspiration.

Ecological correlates of wildlife diseases

The parasite loads appear to differ widely within and between species of free ranging wild mammals. Using data on fecal propagule densities of 29 species of wild mammals from 20 wild life parks in India we tried to identify the ecological factors that are best predictors of parasite loads. Parasite loads were consistently negatively correlated with predatory pressures at both interspecific and intraspecific levels. Carnivores had higher mean parasite loads and the effect of diet and that of predatory pressure appeared to be independent of each other. No other ecological factors were significantly and consistently associated with fecal parasite loads.

Ecological correlates of wildlife diseases

AbstractThe parasite loads appear to differ widely within and between species of free ranging wild mammals. Using data on fecal propagule densities of 29 species of wild mammals from 20 wild life parks in India we tried to identify the ecological factors that are best predictors of parasite loads. Parasite loads were consistently negatively correlated with predatory pressures at both interspecific and intraspecific levels. Carnivores had higher mean parasite loads and the effect of diet and that of predatory pressure appeared to be independent of each other. No other ecological factors were significantly and consistently associated with fecal parasite loads.

Characteristics of Crataerina pallida (Diptera: Hippoboscidae) populations; a nest ectoparasite of the common swift, Apus apus (Aves: Apodidae)

An essential pre-requisite to understanding the nature of a host–parasite relationship is a good knowledge of the parasite’s ecology, including its life history. Despite removing a significant amount of blood from their common swift ( Apus apus) hosts, no detrimental effect of parasitism by the louse fly ( Crataerina pallida) has been found. This may be because little is known of the characteristics of the populations of this parasite. We studied the structure of louse fly populations that may influence its pathogenicity. High levels of prevalence were seen, with 100% of nests being parasitized during 2007 and 2008. Louse fly pupae were found to be aggregated, with a frequency distribution best described by the negative binomial model in 2006–2008. The mean parasitic load per nest was 3.72 ± 2.65 in 2007 and 4.21 ± 3.09 in 2008, much higher than that found in comparative studies. Louse fly numbers declined throughout the swift breeding season. Parasite populations were heavily female biased, except for at the initial and final stages of the nestling period.

Quantification of Parasite Load in Clinical Samples of Leishmaniasis Patients: IL-10 Level Correlates with Parasite Load in Visceral Leishmaniasis

A rapid and accurate method to detect and quantify Leishmania parasite is urgently needed to facilitate early diagnosis of Leishmaniasis and monitoring of antileishmania therapy. In this study, real-time assay was applied to estimate parasite load in clinical samples of visceral leishmaniasis (VL) and post kala-azar dermal leishmaniasis (PKDL) patients. The mean parasite load in blood of VL patients (n = 31) was 8,372 parasites/ml, while the mean parasite load in bone marrow aspirate (BMA) was 194,962 parasites/million nucleated cells (n = 12). Parasite load was undetectable after treatment with amphotericin B (n = 9) in VL, while a residual parasite burden was detected in 2 of 6 patients following treatment with sodium antimony gluconate. Further, circulating levels of IFN-γ, TNF-α, IL-10, IL-6, IL-4 and IL-2 were analysed in VL patients (n = 29) by Cytometric Bead Array to evaluate correlation with parasitic load. Interestingly, IL-10 levels correlated significantly with parasite load (r = 0.82, P<0.0001). The mean parasite load in dermal lesions of PKDL patients was 9,502 parasites/µg tissue DNA at pre-treatment stage (n = 25), with no detectable parasites after therapy (n = 5). Parasite burden was distinctly higher (P<0.0001) in nodular lesions (n = 12) (19,586 parasites/µg tissue DNA) compared to papular/macular lesions (n = 13, 193 parasites/µg tissue DNA). Further, chronic PKDL lesions showed significantly (P = 0.0166) higher parasite load in comparison with acute lesions. Results indicate that chronic, nodular cases constitute the major parasite reservoir for anthroponotic transmission. Our results establish that the high parasite load in VL is strongly correlated with a high level of IL-10, implicating IL-10 as a marker of disease severity. The assay is applicable for diagnosis as well as prognosis of both VL and PKDL, providing a simple molecular tool to monitor the efficacy of antileishmanial drugs or vaccines.