Identification of potential inhibitors against the Zika virus using consensus scoring

The Zika virus (ZIKV) is a life threatening pathogen of zoonotic importance with prevalence in some parts of Africa and America. Unfortunately, there is yet to be a single approved vaccine or antiviral drug to treat the diseases and deformations being caused by the Zika virus infection. In this study, about 36 million compounds from MCULE database were virtually screened against a real matured ZIKV protein using a consensus scoring method to get improved hit rates. The consensus scoring method combined the result from the 25 top ranked molecules from both MCULE and Drug Score eXtended (DSX) docking programs which led to the selection of two hit compounds. The inhibition constant (Ki) values of 0.08 and 0.30μm were obtained for the two selected compounds MCULE-8830369631-0-1 and MCULE-9236850811-0-1 respectively, to remark them as hit compounds. The molecular interactions of the two selected hit compounds with the amino acids (ALA 48, ILE 49, ILE 468 and LEU 472) present in the ZIKV protein indicated that they both have similar binding modes. The result of the computationally predicted physicochemical properties including ADMET for the selected compounds showed their great potential in becoming lead compounds upon optimization and thus could be used in treating the Zika virus diseases.

COVID-19: CADD to the rescue

The recent outbreak of the deadly COVID-19 disease, being caused by the novel coronavirus (SARS-CoV-2), has put the world on red alert as it keeps spreading and recording more fatalities. Research efforts are being carried out to curtail the disease from spreading as it has been declared as of global health emergency. Hence, there is an exigent need to identify and design drugs that are capable of curing the infection and hinder its continual spread across the globe. Herein, a computer-aided drug design tool known as the virtual screening method was used to screen a database of 44 million compounds to find compounds that have the potential to inhibit the surface glycoprotein responsible for virus entry and binding. The consensus scoring approach selected three compounds with promising physicochemical properties and favorable molecular interactions with the target protein. These selected compounds can undergo lead optimization to be further developed as drugs that can be used in treating the COVID-19 disease.

Molecular dynamics and combined docking studies for the identification of Zaire ebola virus inhibitors

Ebola virus (EBOV) is a lethal human pathogen with a risk of global spread of its zoonotic infections, and Ebolavirus Zaire specifically has the highest fatality rate amongst other species. There is a need for continuous effort towards having therapies, as a single licensed treatment to neutralize the EBOV is yet to come into reality. This present study virtually screened the MCULE database containing almost 36 million compounds against the structure of a Zaire Ebola viral protein (VP) 35 and a consensus scoring of both MCULE and CLCDDW docking programs remarked five compounds as potential hits. These compounds, with binding energies ranging from -7.9 to -8.9 kcal/mol, were assessed for predictions of their physicochemical and bioactivity properties, as well as absorption, distribution, metabolism, excretion, and toxicity (ADMET) criteria. The results of the 50 ns molecular dynamics simulations showed the presence of dynamic stability between ligand and protein complexes, and the structures remained significantly unchanged at the ligand-binding site throughout the simulation period. Both docking analysis and molecular dynamics simulation studies suggested strong binding affinity towards the receptor cavity and these selected compounds as potential inhibitors against the Zaire Ebola VP 35. With respect to inhibition constant values, bioavailability radar and other physicochemical properties, compound A (MCULE-1018045960-0-1) appeared to be the most promising hit compound. However, the ligand efficiency and ligand efficiency scale need improvement during optimization, and also validation via in vitro and in vivo studies are necessary to finally make a lead compound in treating Ebola virus diseases. Communicated by Ramaswamy H. Sarma.

Molecular Evidence for Local Acquisition of Human Alveolar Echinococcosis in Saskatchewan, Canada

Alveolar echinococcosis (AE) is a life-threatening parasitic disease caused by the zoonotic cestode Echinococcus multilocularis. Our goals were to confirm infection, identify species, and analyze biogeographical origin of metacestode tissues from a suspected human AE case in Saskatchewan, Canada. We conducted polymerase chain reaction (PCR) targeting the nad1 mitochondrial gene for E. multilocularis and the rrnS ribosomal RNA gene for E. granulosus and conducted haplotype analysis at the nad2 locus. Our analysis confirmed AE and indicated that sequences matched infected Saskatchewan coyotes and European E3/E4 haplotypes. The patient had no travel history outside North America. This suggests autochthonous transmission of a European-type strain.

Copro-polymerase chain reaction has higher sensitivity compared to centrifugal fecal flotation in the diagnosis of taeniid cestodes, especially Echinococcus spp, in canids

Prompt and reliable diagnostic tests for taeniid infection in canids are important due to the risk of zoonoses like Echinococcus spp. Current diagnostic methods relying on fecal flotation lack sensitivity and specificity, but this has rarely been quantified due to the challenges in performing adult cestode recovery (the gold standard) in domestic dogs (Canis familiaris). Therefore, we recovered adult Taenia and Echinococcus spp. from intestines, as well as fecal/intestinal material from 484 wild canids trapped for fur in two Canadian provinces (276 foxes - primarily Vulpes vulpes, coyotes - Canis latrans, and wolves - Canis lupus in Québec and 208 coyotes in Saskatchewan). The performances of a newly developed coproPCR for tapeworm DNA detection in dogs, and centrifugal fecal flotation using Sheather's solution, were evaluated against adult cestode recovery. Overall, adult taeniid cestode prevalence (Taenia and/or Echinococcus) was 28 % (95 % CI: 23-33 %) in Québec (62 % (CI: 51-73%) of 74 coyotes, 65 % (CI: 44-82) of 23 wolves, and 11 % (CI: 7-16%) of 179 foxes) and 79 % (CI: 73-84%) of 208 coyotes in Saskatchewan. In Québec, E. canadensis and Taenia spp. were detected in coyotes and wolves, and foxes were only infected with Taenia spp., whereas Saskatchewan coyotes were predominantly infected with E. multilocularis (at significantly higher prevalence, but not intensity, than coyotes in Québec). Compared with centrifugal fecal flotation, the new coproPCR had at least double the sensitivity (58 % vs 23 % in QC coyotes, 57 % vs 23 % in QC wolves, 24 % vs 0% in QC foxes, and 80 % vs 25 % in SK coyotes). Notably, no taeniid eggs were detected on flotations from foxes infected with Taenia spp., and the new coproPCR had highest sensitivity in Saskatchewan coyotes, which were predominantly infected with E. multilocularis. CoproPCR has promising prospects for use in Veterinary clinics and diagnostic laboratories to detect taeniid cestode infections because of its higher sensitivity than faecal flotation methods. This is particularly important for zoonotic Echinococcus spp. where, from a public health perspective, false negatives are a much greater concern than false positives.

Seroprevalence of canine leishmaniasis in Kwara, Oyo and Ogun states of Nigeria

Leishmaniasis is an important tropical disease that is gradually gaining attention in Nigeria. The canine species which include domestic dogs have been named the reservoir host for the zoonotic form of leishmaniasis. The present study was carried out to determine the seroprevalence of canine leishmaniasis in three selected states of Nigeria using indirect enzyme linked immunosorbent assay (ELISA). Two hundred and seventy-three canine sera were tested for Leishmania IgG antibodies. Dogs sampled were grouped into young (<1 year) and adult (>1 year). Total prevalence recorded was 4.40 % (12/273). There was no significant difference (P > 0.05) between sera of hunting (4.83 %) and companion dogs (3.03 %). Furthermore, there was no significant difference (P > 0.05) between young and adults dogs. There was no correlation between sex and prevalence of canine leishmaniasis. However, significant difference (P < 0.05) was observed in the prevalence of each state with Kwara, Oyo and Ogun having 14.63, 3.33 and 1.32 % respectively. The result of this study established the presence of canine leishmaniasis in Oyo, Ogun and Kwara States of Nigeria making the zoonotic form of the disease a possibility.

Host and geographic differences in prevalence and diversity of gastrointestinal helminths of foxes (Vulpes vulpes), coyotes (Canis latrans) and wolves (Canis lupus) in Québec, Canada

Wild canids are hosts to a wide range of parasites and can play a role in transmission of zoonoses. As many parasites are transmitted through food webs, and wild canids are at high trophic levels, parasite prevalence and diversity in wild canids can serve as excellent indicators of ecosystem health. Our main objectives were to update knowledge on the composition of gastrointestinal helminths in wild canids from Québec, Canada, and to describe differences in parasite prevalence and diversity among canid species and regions. Hunters and trappers provided whole carcasses of red foxes (Vulpes vulpes) (N = 176), and intestinal tracts of coyotes (Canis latrans) (N = 77) and gray wolves (Canis lupus) (N = 23) harvested for non-research purposes over the winter of 2016-2017. A modified Stoll's centrifugation sucrose flotation on feces of 250 wild canids was used, and eggs of one family and eight genera of parasitic helminths were recovered: diphyllobothriids, Taenia/Echinococcus spp., Capillaria spp., Toxascaris sp., Toxocara sp., Trichuris sp., Uncinaria sp., and Metorchis sp. Adult Taenia spp. cestodes were recovered from 61 of 276 (22%) canids. Six different species (T. hydatigena, T. twitchelli, T. crassiceps, T. polyacantha, T. krabbei, and T. pisiformis-"like") were differentiated based on DNA sequenced from 65 individual adult cestodes using primers for the nicotinamide adenosine dinucleotide dehydrogenase subunit 1 (ND1) and cytochrome c oxidase subunit 1 (CO1) mitochondrial DNA loci. Alaria sp. trematodes infected 89 of 276 canids (32%). A subset were identified as A. americana at the CO1 locus. The marine trematode Cryptocotyle lingua was reported for the first time in foxes in the province of Québec. These results help us understand more fully the predator-prey relationships within this group of canids. This baseline data in regional parasite prevalence and intensity is critical in order to detect future changes following ecological disturbances due to climate and landscape alterations.

Canine Alveolar Echinococcosis: An Emerging and Costly Introduced Problem in North America

Alveolar echinococcosis (AE), caused by the metacestode of Echinococcus multilocularis, is emerging in both dogs and people in North America. Here, we review 27 cases of canine AE opportunistically reported since the index case was described in 2009 in Western Canada. We describe clinical presentation, diagnosis, treatment, outcome, and source of canine infection, based on genetics of the parasite isolated from some canine cases. Diagnosis of AE was by histopathology and/or PCR on DNA extracted from metacestodes. The median age of dogs at diagnosis was 4 years (range 1-12), which is low compared to neoplasia, the most common differential diagnosis. There was no sex predilection and different breeds were involved, but there were a disproportionate number of boxers and beagles relative to their representation in the general canine population. The most common potential risk factors included contact with wildlife and visits to off leash areas. Abdominal distension was the most common clinical sign at presentation, and medical imaging generally revealed an abdominal mass. On histopathology, protoscoleces were observed in 7 out of 14 dogs. In 7 cases, DNA sequences were most similar to European (versus North American) haplotypes, identical to those recently reported in coyotes as definitive hosts in North America, and different between eastern and western North America, implying multiple introduction events. Dogs that were not treated (n = 6) had 16% survival in the first 100 days in comparison with 82% survival of treated dogs (n = 11). Direct costs to the owner of treating canine AE ranged from 1,317 to 12,655 CAD depending on the situation at the onset of treatment. This study provides important clinical, epidemiological, and economic information for veterinary practitioners and regulators for importation of dogs, and for public health, as dogs with AE may serve as indicators of parasite range expansion and risk to humans.

Intestinal infection with Echinococcus multilocularis in a dog

OBJECTIVE

To raise veterinary awareness of a newly recognized parasitic threat to canine and human health, highlight the increasing availability of molecular parasitological diagnostics and the need to implement best practices of cestocidal use in high-risk dogs.

ANIMAL

A young Boxer dog with vomiting and bloody diarrhea, suspected diagnosis of inflammatory bowel disease.

CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES

Bloodwork revealed inflammation, dehydration, and protein loss, addressed with supportive therapy. Fecal culture revealed only Escherichia coli. On centrifugal flotation, tapeworm eggs (which could be Taenia or Echinococcus spp) and, unusually, adult cestodes of Echinococcus were observed. The referring veterinarian was contacted to initiate immediate treatment with a cestocide due to zoonotic potential. Diagnosis was confirmed with a coproPCR which has higher sensitivity for Echinococcus spp than fecal flotation alone. DNA was identical to an introduced European strain of E multilocularis currently emerging in dogs, people, and wildlife. Since dogs can also self-infect and develop hepatic alveolar echinococcosis (severe and often fatal), this was ruled out using serology and abdominal ultrasound.

TREATMENT AND OUTCOME

Following cestocidal treatment, fecal flotation and coproPCR were negative for eggs and DNA of E multilocularis; however, coccidia were detected and diarrhea resolved following treatment with sulfa-based antibiotics.

CLINICAL RELEVANCE

This dog was serendipitously diagnosed with E multilocularis, acquired through ingestion of a rodent intermediate host likely infected from foxes and coyotes. Therefore, as a dog at high risk of reexposure from eating rodents, regular (ideally monthly) treatment with a labeled cestocide is indicated going forward.

New Geographic Records for Trichinella nativa and Echinococcus canadensis in Coyotes (Canis latrans) from Insular Newfoundland, Canada

Coyotes (Canis latrans) rapidly expanded across North America during the 20th century and in 1987 colonized insular Newfoundland, Canada. Their arrival brought the potential for new predator-prey interactions and the potential for transmission of parasites to naïve populations. Trichinella spp. and Echinococcus spp. are zoonotic parasites not previously reported from the island of Newfoundland, Canada. Muscle samples (diaphragm and tongue) from 153 coyotes and feces from 35/153 coyotes were collected. Larvae of Trichinella spp. were recovered by muscle digestion from 6/153 coyotes (3.9%) and identified using multiplex PCR and Sanger sequencing as T. nativa. Fecal samples were screened for DNA of Echinococcus spp. using qPCR, and intestines from positive animals were examined for adult cestodes. No fecal samples were positive for DNA of E. multilocularis, and 2/35 (5.7%) samples were positive for E. canadensis, of which one was successfully genotyped as the G10 cervid strain. Echinococcus canadensis has not previously been reported on the island of Newfoundland, historically the only region of Canada where Echinococcus spp. was not known to occur. No species of Trichinella have previously been reported on the island. Both parasites are zoonotic, and hunters, trappers, dog owners, and the general public should be aware of these new risks for public health.

New geographic records for Echinococcus canadensis in coyotes and moose from Nova Scotia, Canada

Echinococcus spp. tapeworms can cause serious diseases in mammals, including humans. Within the E. granulosus species complex, metacestodes produce unilocular cysts that are responsible for cystic echinococcosis in animal intermediate hosts. Canids are definitive hosts, harbouring adult cestodes in their intestines. Adult E. canadensis were recovered from the small intestine of 1 of 262 coyotes (Canis latrans) from Nova Scotia, Canada. Subsequently, we found unilocular cysts in lungs and livers of 4 of 8 sympatric moose (Alces alces) from Cape Breton Island. DNA was extracted from three cysts using the Qiagen DNeasy Blood and Tissue kit and assayed by polymerase chain reaction (PCR) with primers (cest4 and cest5) for a 117-bp region of the small subunit of ribosomal RNA of E. granulosus sensu lato, and further validated as E. canadensis G8 using primers targeting nicotinamide adenosine dinucleotide dehydrogenase subunit 1 (ND1) and cytochrome c oxidase subunit 1 (CO1) mitochondrial genes. These are the first records of E. canadensis in any of the three Maritime provinces, which include Nova Scotia, New Brunswick, and Prince Edward Island. The parasite was thought to be absent in this region due to extirpation of wolves (Canis spp.) in the 1800s. These findings suggest that further wildlife surveillance and risk assessment is warranted.

Novel molecular diagnostic (PCR) diagnosis and outcome of intestinal Echinococcus multilocularis in a dog from western Canada

OBJECTIVE

To describe the novel PCR diagnosis and outcome of intestinal Echinococcus multilocularis in a dog.

ANIMAL

A 13-month-old female intact dog with naturally occurring intestinal E multilocularis.

CLINICAL PRESENTATION, PROGRESSION, AND PROCEDURES

The 13-month-old dog initially presented with a reduced appetite and weight loss and then developed hematochezia. The clinical history included a lack of endoparasite preventive care (fecal testing, deworming), exposure to coyotes, fox, sheep, and rodents and the dog had intermittently been fed a raw food diet. Physical examination revealed a thin dog, with a 2/9 body condition score, that was otherwise clinically unremarkable. A fecal sample was submitted for screening for gastrointestinal parasites as part of an infectious disease assessment. The fecal PCR test reported detection of E multilocularis. This result was sequenced as the European haplotype E3/E4. Centrifugal flotation (same sample) did not detect taeniid eggs.

TREATMENT AND OUTCOME

The dog was treated with metronidazole, maropitant, and milbemycin oxime/praziquantel. Clinical improvement was noted within 48 hours. No DNA of E multilocularis was detected in a fecal sample collected approximately 10 days after treatment. The dog's owner was advised to provide monthly deworming (praziquantel) for all dogs on the property and to contact their human health-care provider due to potential zoonotic exposure risk.

CLINICAL RELEVANCE

Increasing detection of E multilocularis is occurring in dogs in Canada and the US. Alveolar echinococcosis can cause severe disease in dogs and humans. Fecal PCR detection and surveillance may alert practitioners to canine intestinal cases and allow dogs to serve as sentinels for human exposure risk.