EPIDEMIOLOGY, ZOONOTIC POTENTIAL, HAEMATOLOGICAL EFFECT, IN VIVO AND IN VITRO CONTROL OF SARCOPTES SCABIEI (LAM) IN ANIMALS AND HUMANS IN KHYBER PAKHTUNKHWA (PAKISTAN)

Abstract

Ectoparasites play a fundamental role in health problems among animals and humans. Sarcoptes scabiei mites (cause of itching and irritation in all individuals) among the ectoparasites are playing a major role in causing heavy economic losses in term of milk and meat in animals and Dermatophagoides mites are the sole parasitic cause of human asthma. The following five studies were conducted to investigate S. scabiei prevalence, zoonotic potential, effect on haematological parameters, in vitro study and in vivo uses in animals and humans and deterrence effect of Nepeta cataria volatiles. Study I- Prevalence of S. scabiei: In the present study 150 buffalo calves, 100 camels, 150 dogs, 150 goats, and 150 humans were examined clinically and microscopically at districts Dera Ismail khan, Bannu, Lakki Marwat, Tank, Karak, Kohat and to their adjacent tribal belt. The prevalence of scabies infestation exhibited epidemic nature in winter season (November to February). During the epidemiological survey the average prevalence across the year recorded was 8.72% in humans, 18.3% in dogs, 14.06% in camels, 7.3% in buffalo calves and 5.3% in goats. Scabies caused by S. scabiei mite can affect any area of the skin, but the lesion found were often most severe on the abdomen, chest, legs, and ears and especially on the pubic regions of studied animals and peoples. Study II- Zoonotic potential: The transmittability nature of Sarcoptes scabiei mites affecting the animals were assessed in humans having contact with S. scabiei infested animals. Though the S. scabiei mites spend their entire life on their respective host, some mites do fall off into the environment due to animal scratching and survive for up to 3 weeks, becomes source of spreading. Taking in consideration the above study 300 families keeping scabies infested dogs, 150 camels drivers, 150 Dairy man and woman dealing with scabietic buffalo calves and 150 nomadic men keeping scabies infested goats were visited. After conducting the study the main zoonotic transmitters found were dogs and camels. The transmittability percentage recorded in dogs (23%), camels (15%), buffalo calves (2%) and goats (2%). For experimental transmittability syringing of 500 live S. scabiei var canis on the back of the healthy buffalo calves, 250 live S. scabiei var bubalis over the back of healthy goats, 400 live S. scabiei var cameli over the back of healthy dogs, 150 live S. scabiei var caprae over the back of healthy camels were carried out. S. scabiei var canis showed 10% transmittability to buffalo calves, S. scabiei var bubalis showed 20% transmittability to goats, S. scabiei var cameli showed 25% transmittability to dogs and S. scabiei var caprae showed 15% transmittability to camels. Study III- Haematological effects: During the present study different blood and biochemical parameters of ten healthy and ten scabies (three groups) suffering individuals from each animal group and human were investigated and their mean averages were assessed. In mites infested animals and humans, total erythrocyte counts (TEC), packed cell volume (PCV), haemoglobin (Hb), haematocrit (HCT), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), were found significantly with lower averages (P < 0.05), while total leucocytes count (TLC), lymphocytes, eosinophil and mean corpuscular volume (MCV) were found with significantly higher averages in comparison to healthy individuals (P < 0.05). Study IV- In Vitro and In Vivo study: Side wise presence of synthetic drug residues in plants and animals food products causing economic losses considered potentially hazardous to animal, human being and environment needs to assess the control methods whether biological or chemical in nature for its perfect use. Studies on the efficacy of some acaricides particularly derived from medicinal plants against S. scabiei mites in vivo and in vitro were carried out on experimental animals and were assessed in laboratory bioassays. For in vitro study 96 wells microtitration plates were used and tested the effects of different medicinal plants on adult scabies mite. In each assay 30 μL of 10, 20 and 30% methanolic extract concentrations of Azadirachta indica, Caparis decidua, Melia azedarach, Nicotiana tobacum , Tecomella undulata, Vitex negundo and 30 μL of Methanol (control wells) were added into 96 wells microtitration plates and then were released 20 mites into each well in three replicates. All the wells were observed upto 72 hrs during incubation. The results were evaluated on the bases of activeness, lethargic movements or stagnant nature. The data showed that 30% concentration of V. negundo was effective treatment for 95% mites mortalities followed by A. indica and N. tobacum with 90%, then C. decidua and T. undulata with 80% and subsequently followed by M. azedarach with 75% mites mortalities. LC50 calculated values through probit analysis for T. undulata with LC50=6.363 mg/100μL was highly effective followed in descending order by V. negundo with LC50=7.160mg/100μL., N. tobacum with LC50=7.820 mg/100μL., A. indica with LC50=8.312 mg/100μL., M. azedarach with LC50=10.697 mg/100μL and C. decidua with LC50=11.869 mg/100μL. In vivo study 10 and 20% methanolic extract concentrations of A. indica , C. decidua, M. azedarach, N. tobacum, T. undulata , V. negundo and ivermectin at the dose rate of 0.2mg/kg b.wt s/c injection in comparison to control (Methyl alcohol) were used on 40 numbers each of buffalo calves, camels, dogs, goats and human on 1st, 7th, 14th and 28th day. Scabicidal affect on individuals was estimated through reduction in the lesion size, regrowth of hairs and reduced mites load. All the scabietic animals and humans were divided into eight groups each containing five individuals for therapeutic purpose. The groups were nominated as B1, C1, D1, G1, H1 for N. tobacum., B2, C2, D2, G2, H2 for V. negundo., B3, C3, D3, G3, H3 for M. azedarach., B4, C4, D4, G4, H4 for A. indica ., B5, C5, D5, G5, H5 for T. undulata., B6, C6, D6, G6, H6 for C. decidua., B7, C7, D7, G7, H7 for ivermectin and B8, C8, D8, G8, H8 for control. After 28th day of topical use of methanolic extracts of medicinal plants cure rate: In (a) A. indica group; ivermectin showed (86, 87, 85, 80 and 81%)., 20% A. indica exhibited (83, 95, 88, 78 and 89% )., 10% A. indica gave (53, 63, 65, 45 and 65%) cure rate; In (b) C. decidua group; ivermectin showed (84, 81, 83, 85, 81%)., 20% C. decidua exhibited (68, 76, 77, 73, 79%)., 10% C. decidua gave (43, 46, 42, 42, 51%); In (c) M. azedarach group; Ivermectin exhibited (84, 85, 85, 80, 83% )., 20% M. azedarach gave (75, 83, 78, 79, 79%)., 10% M. azedarach indicated (49, 49, 57, 42, 58%); In (d) N. tobacum group; ivermectin showed (85, 86, 86, 83, 80%)., 20% N. tobacum indicated (88, 85, 85, 89, 78%)., 10% N. tobacum exhibited (60, 71, 71, 56, 64%); In (e) T. undulata group; ivermectin showed (69, 56, 71, 49, 69%)., 20% T. undulata revealed (44, 54, 58, 33, 45%).,10% T. undulata indicated (34, 37, 32, 28, 35%); In (f) V. negundo group; ivermectin showed (81, 84, 83, 81, 84%)., 20% V. negundo exhibited (73, 75, 77, 69, 78%)., 10% V. negundo showed (43, 46, 42, 42, 61%) and all the control groups did not showed any curing signs in buffalo calves, camels, dogs, goats and human respectively. Study V- Deterrence effect of Nepeta cataria volatile oils: The house dust mite, the major cause of human Asthma whose control is easy through plant origin essential oils as compared to Asthma treatment. Instead of the current acaricidal bioassays, an alternate pathway of Y-tube olfactometer technique was used. Both the mites species (Dermatophagoides farinae and Dermatophagoides pteronyssinus) showed significantly higher rebounded back rates from the arm having different concentrations of T2 and T5 chemotypes (10μg, 1μg, 0.1μg and 0.01μg) used in adding together to fish flakes (10μg) each. T2-chemotype verses hexane gave 40% versus 16%, 45% versus 30%, 47.5% versus 17.5% and 30% versus 28.5%; while T5-chemotype versus hexane gave 47.5% versus 17.5%, 50% versus 17.5%, 42.5% versus 25% and 35% versus 20% repellence at the concentration of 10μg, 1μg, 0.1μg and 0.01μg of both chemotypes respectively. They were compared to the distilled hexane in alternate arm and their significance probability noted was, (P < 0.001) except 0.01μg concentration in T2-chemotype. In T5- chemotype the lowest dose of 0.01 μg/ml of hexane were also found statistically significant regarding the repellence response. Before checking the repellent response of Nepeta cataria volatiles chemotypes, the house dust mites were bio assayed for the attractant response towards fish flakes verses distilled hexane, where fish flakes were found more significantly attractive than distilled hexanes (P<0.001).Our study shows that the Nepetalactones and Caryophyllene both present in the chemotypes T2 and T5 exhibits both narcotic and repellent actions for D. farinae and D. pteronyssinus, and can be used potentially as repellent for house dust mite control. Key words: Azadirachta indica, Epidemiology, Haematological study, Nicotiana tobacum, Olfactometer, Vitex negundo, Y-tube and Zoonosis.