Very little information is available regarding the demographics of the demodicosis in canines of Kathmandu valley and in Nepal as a whole. In this study, we determined the prevalence of the demodicosis and its associated risk factors from 110 canines of Kathmandu valley including both sheltered and free-roaming. The skin scrapping collected was dissolved in 10% KOH for the microscopic diagnosis of the mites. The overall prevalence of demodectic mange was found to be 29.1%. There was significant difference (p<0.05) between the prevalence rate among puppy (49.0%), adult (6.9%) and senior (33.33%). Whereas, there was no significant difference (p>0.05) between the prevalence rate among female (22.9%) and male (36.7%). Similarly, there was no significant difference (p>0.05) between the prevalence rate among short hair (40.7%), medium (25.67%) and long hair (28.5%). The association between the prevalence rate among good health status (10.7%) and poor health status (55.5%) is significant (p<0.05). Similarly, there was significant difference (p<0.05) between the prevalence rate among the free-roaming (48.9%) and the owned dogs (13.1%). At last, there was no significant association (p>0.05) between the prevalence rate among the pure breed (27.7%), cross (25.9%) and mongrel (37.5%). This study shows that demodectic mange is somewhat serious skin infection in canines of Kathmandu valley. The high significant association of age, health status and management with its prevalence suggests that the disease is more common in dogs which are left uncared and whose immune system is disturbed. Whereas, sex, breed and type of the hair of the dog did not have such significant relation with its prevalence.  As demodicosis is a huge problem in street dogs, concerned organizations and authorities should develop proper planning for street dog management and their health care. Int J Appl Sci Biotechnol, Vol 3(3): 459-463

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Organic dust (OD) exposure in animal production industries poses serious respiratory and other health risks. OD consists of microbial products and particulate matter and OD exposure induced respiratory inflammation is under intense investigation. However, the effect of OD exposure on brain largely remains unknown. Recently, we have shown that OD exposure of brain microglial cells induces an inflammatory phenotype with the release of mitochondrial DNA (mt-DNA). Therefore, we tested a hypothesis that ODexposure induced secreted mt-DNA signaling drives the inflammation. OD samples were collected from commercial swine operations and a filter sterilized OD extract (ODE) was prepared. Mouse (C57BL/6) microglial cell line was treated with medium or ODE (5%) for 48 hours along with either PBS or mitoapocynin (MA, 10 μM, NOX-2 inhibitor). Microglia treated with control or anti-STING siRNA were exposed to medium or ODE. Next, mouse (C57BL/6) pups were euthanized under an approved protocol, organotypic brain slice cultures (BSCs) were prepared and exposed to medium or ODE with or without MA treatment daily for five days. Culture supernatant, cell pellets and mt-free cytosolic fractions were processed to quantify mt-superoxide, mt-DNA, cytochrome C, TFAM, mitochondrial stress markers and mt-DNA induced signaling via cGAS-STING and TLR9. Data were analyzed using one-way ANOVA and posthoc tests. A p value of ≤ 0.05 was considered significant. ODE exposure increased the mt-superoxide formation andMA treatment decreased the ODE-induced mt-DNA release into cytosol. ODE exposure increased the cytochrome C and TFAM levels. ODE increased MFN1/2 and PINK1 but not DRP1 and MA treatment decreased the MFN2 expression. MA treatment decreased the ODE-exposure induced mt-DNA signaling via cGAS-STING and TLR9. Anti-STING siRNA decreased the ODE-induced increase in IRF3, IFN-β and Iba1 expression. In BSCs, MA-treatment decreased the ODE induced TNF-α, IL-6 and MFN1.Taken together, OD exposure induced mt-DNA signaling could be curtailed through mitochondrial NOX-2 inhibition or STING suppression to reduce neuroinflammation.

ABSTRACTOrganic dust (OD) exposure in animal production industries poses serious respiratory and other health risks. OD consists of microbial products and particulate matter and OD exposure induced respiratory inflammation is under intense investigation. However, the effect of OD exposure on brain largely remains unknown. Recently, we have shown that OD exposure of brain microglial cells induces an inflammatory phenotype with the release of mitochondrial DNA (mt-DNA). Therefore, we tested a hypothesis that OD-exposure induced secreted mt-DNA signaling drives the inflammation. OD samples were collected from commercial swine operations and a filter sterilized OD extract (ODE) was prepared. Mouse (C57BL/6) microglial cell line was treated with medium or ODE (5%) for 48 hours along with either PBS or mitoapocynin (MA, 10 μM, NOX-2 inhibitor). Microglia treated with control or anti-STING siRNA were exposed to medium or ODE. Next, mouse (C57BL/6) pups were euthanized under an approved protocol, organotypic brain slice cultures (BSCs) were prepared and exposed to medium or ODE with or without MA treatment daily for five days. Culture supernatant, cell pellets and mt-free cytosolic fractions were processed to quantify mt-superoxide, mt-DNA, cytochrome C, TFAM, mitochondrial stress markers and mt-DNA induced signaling via cGAS-STING and TLR9. Data were analyzed using one-way ANOVA and post-hoc tests. A p value of ≤ 0.05 was considered significant. ODE exposure increased the mt-superoxide formation andMA treatment decreased the ODE-induced mt-DNA release into cytosol. ODE exposure increased the cytochrome C and TFAM levels. ODE increased MFN1/2 and PINK1 but not DRP1 and MA treatment decreased the MFN2 expression. MA treatment decreased the ODE-exposure induced mt-DNA signaling via cGAS-STING and TLR9. Anti-STING siRNA decreased the ODE-induced increase in IRF3, IFN-β and Iba1 expression. In BSCs, MA-treatment decreased the ODE induced TNF-α, IL-6 and MFN1. Taken together, OD exposure induced mt-DNA signaling could be curtailed through mitochondrial NOX-2 inhibition or STING suppression to reduce neuroinflammation.

Agriculture workers report various respiratory symptoms owing to occupational exposure to organic dust (OD) and various gases. Previously, we demonstrated that pre-exposure to hydrogen sulfide (H2S) alters the host response to OD and induces oxidative stress. Nrf2 is a master-regulator of host antioxidant response and exposures to toxicants is known to reduce Nrf2 activity. The OD exposure-induced lung inflammation is known to increase susceptibility to a secondary microbial infection. We tested the hypothesis that repeated exposure to OD or H2S leads to loss of Nrf2, loss of epithelial cell integrity and that activation of Nrf2 rescues this epithelial barrier dysfunction. Primary normal human bronchial epithelial (NHBE) cells or mouse precision cut-lung slices (PCLS) were treated with media, swine confinement facility organic dust extract (ODE) or H2S or ODE+H2S for one or five days. Cells were also pretreated with vehicle control (DMSO) or RTA-408, a Nrf2 activator. Acute exposure to H2S and ODE+H2S altered the cell morphology, decreased the viability as per the MTT assay, and reduced the Nrf2 expression as well as increased the keap1 levels in NHBE cells. Repeated exposure to ODE or H2S or ODE+H2S induced oxidative stress and cytokine production, decreased tight junction protein occludin and cytoskeletal protein ezrin expression, disrupted epithelial integrity and resulted in increased Klebsiella pneumoniae invasion. RTA-408 (pharmacological activator of Nrf2) activated Nrf2 by decreasing keap1 levels and reduced ODE+H2S-induced changes including reversing loss of barrier integrity, inflammatory cytokine production and microbial invasion in PCLS but not in NHBE cell model. We conclude that Nrf2 activation has a partial protective function against ODE and H2S.