Extensive Aberrant Migration of Onchocerca lupi in a Dog.

A 13-year-old Labrador retriever mixed breed dog from Arizona was presented for evaluation of an acute onset of a head tilt as well as vocalization and head shaking upon palpation of the ears. The dog was previously treated for ocular onchocercosis associated with the right eye 10 years earlier. Ophthalmic examination at presentation revealed irregular, tan-colored, masses on the sclera of both eyes. Otoscopic evaluation of the left ear was limited because the canals were stenotic and inaccessible. Cytology did not reveal any infectious etiologies and the dog was subsequently treated with an anti-inflammatory dose of prednisone for 10 days. Two weeks later the dog developed a mild dysphonia and stridor that eventually progressed to include difficulty breathing. The dog was euthanized and postmortem examination revealed white-to-tan nodules identified in the episclera, trachea, subcutis around the nares, external ear canals, and within the fascia overlying the temporalis muscle, as well as in the parietal pleura, and pericardium. There was also a large mass that obliterated the laryngeal cartilage that partially occluded the laryngeal opening. Microscopically, the described nodules consisted predominately of lakes of abundant mineralized debris, admixed with granulomatous inflammation centered around degenerate nematodes that were subsequently confirmed by PCR and sequence analysis to be Onchocerca lupi. The veterinary literature is comprised of only 2 reports that describe aberrant O. lupi migration to the trachea and larynx. Here, we provide the first detailed description of a dog with extensive aberrant onchocercosis.

Geostatistical modelling enables efficient safety assessment for mass drug administration with ivermectin in Loa loa endemic areas through a combined antibody and LoaScope testing strategy for elimination of onchocerciasis.

The elimination of onchocerciasis through community-based Mass Drug Administration (MDA) of ivermectin (Mectizan) is hampered by co-endemicity of Loa loa, as individuals who are highly co-infected with Loa loa parasites can suffer serious and occasionally fatal neurological reactions from the drug. The test-and-not-treat strategy of testing all individuals participating in MDA has some operational constraints including the cost and limited availability of LoaScope diagnostic tools. As a result, a Loa loa Antibody (Ab) Rapid Test was developed to offer a complementary way of determining the prevalence of loiasis. We develop a joint geostatistical modelling framework for the analysis of Ab and Loascope data to delineate whether an area is safe for MDA. Our results support the use of a two-stage strategy, in which Ab testing is used to identify areas that, with acceptably high probability, are safe or unsafe for MDA, followed by Loascope testing in areas whose safety status is uncertain. This work therefore contributes to the global effort towards the elimination of onchocerciasis as a public health problem by potentially reducing the time and cost required to establish whether an area is safe for MDA.

Onchocerca ochengi male worms implanted in SCID mice and Gerbil: Relationship between microfilaridermia status of cows, nodular worm viability and fertility and worm survival in the rodents.

BACKGROUND: Current treatment options for onchocerciasis are sub-optimal, prompting research and development of a safe cure (macrofilaricide). Onchocerca ochengi, a parasite of cattle, is used as a close surrogate for the human parasite O. volvulus in a murine model for pre-clinical screening of macrofilaricides. Skin from naturally infected cattle have been used in previous studies as a reliable source of parasite material. However, there is limited knowledge on how source-related factors such as the microfilaridermia status of the cattle, the nodule load and nodular worm viability may affect survival of male O. ochengi worms implanted in the rodent hosts. Such relationships were investigated in this study. METHODS: Dermal tissue and nodules were obtained from Gudali cattle, dissected and cultured to obtain migrating microfilariae (mf) and male worms. Emerged male worms were implanted into SCID mice and Gerbils (Meriones unguiculatus) and recovery rates were determined upon 42 days post implantation. Finally, nodules were processed for histology and embryogram analyses to assess the nodular worm viability and fertility, respectively. RESULTS: Of the 69 cattle sampled, 24 (34.8%) were mf+ and 45 (65.2%) were mf-. The mean nodule loads were 180.5 ± 117.7 (mf+) and 110.6 ± 102.7 (mf-) (p = 0.0186). The mean male worm harvest from nodules were 76.8 ± 120.3 and 47.2 ± 33.4 (p = 0.2488) for mf+ and mf- cattle, respectively. The number of male worms per 100 nodules were 57/100 and 46/100 nodules for mf+ and mf- cows, respectively. Female worms from nodules of mf- cows had higher counts of both normal and abnormal embryos with higher proportions of dead nodular worms evinced by histology compared to those from mf+ cows. A total of 651 worms were implanted into mice and gerbils, out of which 129 (19.81%) were recovered. Logistic regression analysis indicated that the microfilaridermia status of the cattle (presence of mf) (OR = 4.3319; P = 0.001) is the single most important predictor of the success of male worm recovery after implantation into rodents. CONCLUSION: Microfilaridermic cattle provide a promising source of adult O. ochengi. Male worms from this group of cattle have a better success rate of survival in a murine implant model. Nevertheless, in the programmatic point of view, amicrofilaridermic Gudali cattle would still constitute an important source of O. ochengi male worms with relatively good viability after implantation into rodents.

How does onchocerciasis-related skin and eye disease in Africa depend on cumulative exposure to infection and mass treatment?

BACKGROUND: Onchocerciasis (river-blindness) in Africa is targeted for elimination through mass drug administration (MDA) with ivermectin. Onchocerciasis may cause various types of skin and eye disease. Predicting the impact of MDA on onchocercal morbidity is useful for future policy development. Here, we introduce a new disease module within the established ONCHOSIM model to predict trends over time in prevalence of onchocercal morbidity. METHODS: We developed novel generic model concepts for development of symptoms due to cumulative exposure to dead microfilariae, accommodating both reversible (acute) and irreversible (chronic) symptoms. The model was calibrated to reproduce pre-control age patterns and associations between prevalences of infection, eye disease, and various types of skin disease as observed in a large set of population-based studies. We then used the new disease module to predict the impact of MDA on morbidity prevalence over a 30-year time frame for various scenarios. RESULTS: ONCHOSIM reproduced observed age-patterns in disease and community-level associations between infection and disease reasonably well. For highly endemic settings with 30 years of annual MDA at 60% coverage, the model predicted a 70% to 89% reduction in prevalence of chronic morbidity. This relative decline was similar with higher MDA coverage and only somewhat higher for settings with lower pre-control endemicity. The decline in prevalence was lowest for mild depigmentation and visual impairment. The prevalence of acute clinical manifestations (severe itch, reactive skin disease) declined by 95% to 100% after 30 years of annual MDA, regardless of pre-control endemicity. CONCLUSION: We present generic model concepts for predicting trends in acute and chronic symptoms due to history of exposure to parasitic worm infections, and apply this to onchocerciasis. Our predictions suggest that onchocercal morbidity, in particular chronic manifestations, will remain a public health concern in many epidemiological settings in Africa, even after 30 years of MDA.

Autochthonous, zoonotic Onchocerca lupi in a South Texas dog, United States.

BACKGROUND: Onchocerca lupi is an emerging, zoonotic filarioid nematode associated with ocular disease in companion animals in North America and the Old World. The areas where this parasite is assumed to be endemic in the USA comprise southwestern states. Thus far, all cases reported outside of the southwest are associated with travel or animal movement. METHODS: An 11-year-old, castrated male Pitbull dog from McAllen, Hidalgo County, southern Texas, with no travel history, was diagnosed with a perforating corneal ulceration of the right eye. Enucleation was performed and tissues submitted for histopathology. RESULTS: Histologically, sections of two filarioid nematodes were observed. DNA was extracted from formalin-fixed paraffin-embedded tissue using a commercial kit. We performed PCR targeting the cox1 gene of the mitochondrial DNA, followed by sequencing and phylogenetic analysis. Altogether, these results confirmed the identification of the nematode specimens as O. lupi, phylogenetically belonging to haplotype 1. CONCLUSION: We report the first autochthonous case of O. lupi in a dog from Hidalgo County, southern Texas, USA. Our finding suggests Texas as an additional state where this zoonotic nematode is endemic. Further investigations are required to understand the epidemiology of this parasite along the USA/Mexico border.

The Eagle effect in the Wolbachia-worm symbiosis.

BACKGROUND: Onchocerciasis (river blindness) and lymphatic filariasis (elephantiasis) are two human neglected tropical diseases that cause major disabilities. Mass administration of drugs targeting the microfilarial stage has reduced transmission and eliminated these diseases in several countries but a macrofilaricidal drug that kills or sterilizes the adult worms is critically needed to eradicate the diseases. The causative agents of onchocerciasis and lymphatic filariasis are filarial worms that harbor the endosymbiotic bacterium Wolbachia. Because filarial worms depend on Wolbachia for reproduction and survival, drugs targeting Wolbachia hold great promise as a means to eliminate these diseases. METHODS: To better understand the relationship between Wolbachia and its worm host, adult Brugia pahangi were exposed to varying concentrations of doxycycline, minocycline, tetracycline and rifampicin in vitro and assessed for Wolbachia numbers and worm motility. Worm motility was monitored using the Worminator system, and Wolbachia titers were assessed by qPCR of the single copy gene wsp from Wolbachia and gst from Brugia to calculate IC50s and in time course experiments. Confocal microscopy was also used to quantify Wolbachia located at the distal tip region of worm ovaries to assess the effects of antibiotic treatment in this region of the worm where Wolbachia are transmitted vertically to the microfilarial stage. RESULTS: Worms treated with higher concentrations of antibiotics had higher Wolbachia titers, i.e. as antibiotic concentrations increased there was a corresponding increase in Wolbachia titers. As the concentration of antibiotic increased, worms stopped moving and never recovered despite maintaining Wolbachia titers comparable to controls. Thus, worms were rendered moribund by the higher concentrations of antibiotics but Wolbachia persisted suggesting that these antibiotics may act directly on the worms at high concentration. Surprisingly, in contrast to these results, antibiotics given at low concentrations reduced Wolbachia titers. CONCLUSION: Wolbachia in B. pahangi display a counterintuitive dose response known as the "Eagle effect." This effect in Wolbachia suggests a common underlying mechanism that allows diverse bacterial and fungal species to persist despite exposure to high concentrations of antimicrobial compounds. To our knowledge this is the first report of this phenomenon occurring in an intracellular endosymbiont, Wolbachia, in its filarial host.

Assessing the potential cross-reactivity using a commercial heartworm ELISA kits of serum from dogs naturally infected with Onchocerca lupi.

Onchocerca lupi is an emerging zoonotic parasite of dogs, endemic to the southwestern USA and areas of the Old World. Currently, there are no specific serological diagnostic tests able to detect O. lupi infection. Recent literature has demonstrated that commercially available heartworm antigen tests, despite being highly sensitive, may cross-react with infections by other filarid nematodes. There is no information on potential cross-reactivity of such tests in serum of dogs infected with O. lupi. Our objective was to assess serum samples of dogs naturally-infected with O. lupi for potential cross-reactivity before and after heat-treatment using a commercial heartworm ELISA kit. We obtained serum from 23 dogs naturally-infected with O. lupi. These dogs presented with ocular disease, and were consulted to schedule either surgical removal of ocular nodules due to infection or enucleation. Samples were tested in triplicate using the DiroCHEK® Heartworm Antigen Test kit (Synbiotics Corporation, Zoetis, Kalamazoo, MI, USA) following the manufacturers' protocol pre- and post-heat-treatment. Samples were heat-treated using a dry heat block at 103 °C for 10 min and then centrifuged at 1818×g for 20 min. Out of a total of 23 dogs, 19 (82.6 %) had no antigen detected regardless of heat-treatment, three dogs tested positive before and after heat-treatment, and a single dog turned positive after heat-treatment. These three dogs that were positive before and after heat-treatment were confirmedly co-infected with Dirofilaria immitis by the veterinarians responsible for these cases, and we were unable to get the history or follow up with the dog that turned positive post-heat-treatment only. Our data suggest that O. lupi infections should not result in false-positives when using the DiroCHEK® in dog serum, before or after heat-treatment. Dogs with clinical ocular onchocercosis that test antigen-positive in DiroCHEK® are likely co-infected with D. immitis, and should be further tested, including evaluation of microfilariae in blood and diagnostic imaging. If heartworm infection is confirmed, the animals should be enrolled in the recommended treatment protocol in accordance to the guidelines of the American Heartworm Society or other local organizations.

Survey of infection and determination of the transmission vector of Onchocerca fasciata in camels (Camelus bactrianus) in Inner Mongolia, China.

Onchocerciasis in camels is caused by adult Onchocerca spp. and results in great economic losses to the camel industry. However, only a few studies on Onchocerca have been conducted, especially regarding the intermediate host and vector(s). In the present study, 192 camels were examined from December and January during 2013 and 2016, and the filarial larvae suspected to be Onchocerca spp. were further identified. Furthermore, aquatic dipteran insects in the living environment of camels were collected from May to September between 2013 and 2017 and dissected. Eventually, onchocercal lesions were observed in 95 of 192 (49%) camels and the captured insects were classified into 49 species from 42 genera in 21 families, among which 18 species were newly recorded in Inner Mongolia and 14 were haematophagous species. The filarial larvae were found in Culicoides puncticollis and identified as Onchocerca fasciata, indicating that C. puncticollis is the vector of O. fasciata in Inner Mongolia. These findings provide an estimate of onchocerciasis infection in camels and an alternative method of identifying insects and screening vectors using molecular methods. Important data are also provided for the diagnosis and control of onchocerciasis, thereby further filling the gap in knowledge regarding transmission vectors in China.

Impact of Ivermectin Mass Drug Administration for Lymphatic Filariasis on Scabies in Eight Villages in Kongwa District, Tanzania.

Scabies was recently added to the World Health Organization list of neglected tropical diseases. The ability to treat scabies with oral ivermectin makes a mass drug administration (MDA) campaign a feasible option for scabies control. Ivermectin MDA in communities endemic for lymphatic filariasis (LF) or onchocerciasis may already be having an impact on scabies. We examined the effect of ivermectin MDA for LF on scabies prevalence over 4 years in eight Tanzanian villages. At baseline, 4.4% (95% confidence interval [CI]: 3.7-5.4) of individuals tested positive for scabies, decreasing to 0.84% (95% CI: 0.51-1.4) after one round of ivermectin MDA but increased in Year 3 (2.5% [95% CI: 1.9-3.3]) and Year 4 (2.9% [95% CI: 2.2-3.8]). Most scabies cases were seen in children younger than 15 years. The data suggest that single-dose ivermectin MDA may not be effective in attaining long-term decreases when scabies prevalence is less than 5%.

Identifying co-endemic areas for major filarial infections in sub-Saharan Africa: seeking synergies and preventing severe adverse events during mass drug administration campaigns.

BACKGROUND: Onchocerciasis and lymphatic filariasis (LF) are major filarial infections targeted for elimination in most endemic sub-Saharan Africa (SSA) countries by 2020/2025. The current control strategies are built upon community-directed mass administration of ivermectin (CDTI) for onchocerciasis, and ivermectin plus albendazole for LF, with evidence pointing towards the potential for novel drug regimens. When distributing microfilaricides however, considerable care is needed to minimise the risk of severe adverse events (SAEs) in areas that are co-endemic for onchocerciasis or LF and loiasis. This work aims to combine previously published predictive risk maps for onchocerciasis, LF and loiasis to (i) explore the scale of spatial heterogeneity in co-distributions, (ii) delineate target populations for different treatment strategies, and (iii) quantify populations at risk of SAEs across the continent. METHODS: Geographical co-endemicity of filarial infections prior to the implementation of large-scale mass treatment interventions was analysed by combining a contemporary LF endemicity map with predictive prevalence maps of onchocerciasis and loiasis. Potential treatment strategies were geographically delineated according to the level of co-endemicity and estimated transmission intensity. RESULTS: In total, an estimated 251 million people live in areas of LF and/or onchocerciasis transmission in SSA, based on 2015 population estimates. Of these, 96 million live in areas co-endemic for both LF and onchocerciasis, providing opportunities for integrated control programmes, and 83 million live in LF-monoendemic areas potentially targetable for the novel ivermectin-diethylcarbamazine-albendazole (IDA) triple therapy. Only 4% of the at-risk population live in areas co-endemic with high loiasis transmission, representing up to 1.2 million individuals at high risk of experiencing SAEs if treated with ivermectin. In these areas, alternative treatment strategies should be explored, including biannual albendazole monotherapy for LF (1.4 million individuals) and 'test-and-treat' strategies (8.7 million individuals) for onchocerciasis. CONCLUSIONS: These maps are intended to initiate discussion around the potential for tailored treatment strategies, and highlight populations at risk of SAEs. Further work is required to test and refine strategies in programmatic settings, providing the empirical evidence needed to guide efforts towards the 2020/2025 goals and beyond.

Litomosoides silvai (Nematoda: Onchocercidae) parasitizing Akodon montensis (Rodentia: Cricetidae) in the southern region of Brazil / Litomosoides silvai (Nematoda: Onchocercidae) parasitando Akodon montensis (Rodentia: Cricetidae) na região Sul do Brasil

Abstract In the present study, Litomosoides silvai parasitizing Akodon montensis in the southern region of Brazil is reported for the first time. New morphological information is provided for some structures of this nematode species, such as a flattened cephalic extremity, presence of two dorsal cephalic papillae, female tail with a constriction at its tip, "s" shaped vagina, spicules characteristic of the carinii species group and microfilaria tail constricted at the tip. This nematode was found parasitizing the thoracic cavity with a prevalence of 10% (2/20), mean intensity of 4 (6/2), mean abundance of 0.4 (8/20) and range of infection of 2-6 specimens per host, in southern Brazil. This occurrence of L. silvai in A. montensis is a new geographical record for southern Brazil, in the Upper Paraná Atlantic Forest ecoregion of the northwestern region of Rio Grande do Sul, which is part of the Atlantic Forest biome.

Resumo No presente estudo é relatado pela primeira vez Litomosoides silvai parasitando Akodon montensis coletados na região Sul do Brasil. Foram fornecidas novas informações morfológicas para algumas estruturas desta espécie de nematódeo, tais como extremidade cefálica achatada, a presença de duas papilas cefálicas dorsais, cauda das fêmeas com uma constrição na ponta da cauda, vagina em forma de "s", espículas de característica do grupo de espécies de carinii e cauda da microfilária com constrição na ponta. Este nematódeo parasitava a cavidade torácica com uma prevalência de 10% (2/20), intensidade média de 4 (8/2) e abundância média de 0,4 (8/20), e intervalo de infecção de 2-6 espécimes por hospedeiro no Sul do Brasil. A ocorrência de L. silvai em A. montensis é um novo registro geográfico, no sul do Brasil, a noroeste do estado do Rio Grande do Sul, na ecorregião da Mata Atlântica do Alto Paraná, parte do bioma da Mata Atlântica.

Litomosoides silvai (Nematoda: Onchocercidae) parasitizing Akodon montensis (Rodentia: Cricetidae) in the southern region of Brazil.

In the present study, Litomosoides silvai parasitizing Akodon montensis in the southern region of Brazil is reported for the first time. New morphological information is provided for some structures of this nematode species, such as a flattened cephalic extremity, presence of two dorsal cephalic papillae, female tail with a constriction at its tip, "s" shaped vagina, spicules characteristic of the carinii species group and microfilaria tail constricted at the tip. This nematode was found parasitizing the thoracic cavity with a prevalence of 10% (2/20), mean intensity of 4 (6/2), mean abundance of 0.4 (8/20) and range of infection of 2-6 specimens per host, in southern Brazil. This occurrence of L. silvai in A. montensis is a new geographical record for southern Brazil, in the Upper Paraná Atlantic Forest ecoregion of the northwestern region of Rio Grande do Sul, which is part of the Atlantic Forest biome.

Whence river blindness? The domestication of mammals and host-parasite co-evolution in the nematode genus Onchocerca.

The genus Onchocerca includes 34 described species and represents one of the largest genera of the filarial nematodes within the family Onchocercidae. Representative members of this genus are mainly parasites of ungulates, with some exceptions such as Onchocerca lupi and Onchocerca volvulus, infecting carnivores and/or humans. For a long time, the evolutionary relationships amongst onchocercids remained poorly studied, as the systematics of this genus was impaired by the high morphological variability of species included in the taxon. Although some molecular phylogenies were developed, these studies were mainly focused on bovine Onchocerca spp. and O. volvulus, including assessments of Wolbachia endosymbionts. In the present study, we analysed 13 Onchocerca spp. from a larger host spectrum using a panel of seven different genes. Analysis of the coxI marker supports its usefulness for the identification of species within the genus. The evolutionary history of the genus has been herein revised by multi-gene phylogenies, presenting three strongly supported clades of Onchocerca spp. Analyses of co-evolutionary scenarios between Onchocerca and their vertebrate hosts underline the effect of domestication on Onchocerca speciation. Our study indicates that a host switch event occurred between Bovidae, Canidae and humans. Cophylogenetic analyses between Onchocerca and the endosymbiotic bacterium Wolbachia indicate the strongest co-evolutionary pattern ever registered within the filarial nematodes. Finally, this dataset indicates that the clade composed by O. lupi, Onchocerca gutturosa, Onchocerca lienalis, Onchocerca ochengi and O. volvulus derived from recent speciation.

Filarial infection caused by Onchocerca boehmi (Supperer, 1953) in a horse from Italy.

Equids can be infected by a range of skin-dwelling filarial nematodes, including four species of the genus Onchocerca. Current literature on equine onchocercosis is fragmentary and often limited to isolated case reports. The present study aimed to describe a clinical case of equine onchocercosis caused by Onchocerca boehmi (Supperer, 1953) (syn. Elaeophora boehmi) in an 8-year-old gelding Belgian show jumper from northern Italy. The horse was presented with a firm and painless mass on the proximal third of the right metacarpal region. Ultrasound examination showed a peritendinous enlargement around the palmaro-lateral area of the tendons, characterized by an elongated hypoechoic and well-defined structure, embedding a coiled hyperechoic line. The metacarpal nodule was resected and histologically examined. Fragments of a parasitic nematode were detected, isolated and examined. The morphological analysis allowed identifying the nematode as O. boehmi. In addition, total genomic DNA was extracted from individual fragments using a commercial kit for the nematode identification and a comparative sequence analysis of the nematode cytochrome oxidase subunit 1 (cox1) sequence with data available in the GenBankTM database revealed the closest identity (i.e. 91 %) with that of Onchocerca lupi. Thus far, O. boehmi has only been reported in Austria and Iran, and information about its life-cycle and vectors is lacking. The systematic position of this species within the genus Onchocerca, not in Elaeophora where it was originally described, is in concordance with the morphological and molecular analysis. In this article, we describe the first autochthonous case of equine onchocercosis in Italy caused by O. boehmi and discuss novel parasitological, clinical, and pathological data on these pathogens of horses.

25 Years of the Onchocerca ochengi Model.

Although of limited veterinary significance, Onchocerca ochengi has become famous as a natural model or 'analogue' of human onchocerciasis (river blindness), which is caused by Onchocerca volvulus. On the basis of both morphological and molecular criteria, O. ochengi is the closest extant relative of O. volvulus and shares several key natural history traits with the human pathogen. These include exploitation of the same group of insect vectors (blackflies of the Simulium damnosum complex) and formation of collagenous nodules with a similar histological structure to human nodules. Here, we review the contribution of this natural system to drug and vaccine discovery efforts, as well as to our basic biological understanding of Onchocerca spp., over the past quarter-century.

Stage-specific Proteomes from Onchocerca ochengi, Sister Species of the Human River Blindness Parasite, Uncover Adaptations to a Nodular Lifestyle.

Despite 40 years of control efforts, onchocerciasis (river blindness) remains one of the most important neglected tropical diseases, with 17 million people affected. The etiological agent, Onchocerca volvulus, is a filarial nematode with a complex lifecycle involving several distinct stages in the definitive host and blackfly vector. The challenges of obtaining sufficient material have prevented high-throughput studies and the development of novel strategies for disease control and diagnosis. Here, we utilize the closest relative of O. volvulus, the bovine parasite Onchocerca ochengi, to compare stage-specific proteomes and host-parasite interactions within the secretome. We identified a total of 4260 unique O. ochengi proteins from adult males and females, infective larvae, intrauterine microfilariae, and fluid from intradermal nodules. In addition, 135 proteins were detected from the obligate Wolbachia symbiont. Observed protein families that were enriched in all whole body extracts relative to the complete search database included immunoglobulin-domain proteins, whereas redox and detoxification enzymes and proteins involved in intracellular transport displayed stage-specific overrepresentation. Unexpectedly, the larval stages exhibited enrichment for several mitochondrial-related protein families, including members of peptidase family M16 and proteins which mediate mitochondrial fission and fusion. Quantification of proteins across the lifecycle using the Hi-3 approach supported these qualitative analyses. In nodule fluid, we identified 94 O. ochengi secreted proteins, including homologs of transforming growth factor-ß and a second member of a novel 6-ShK toxin domain family, which was originally described from a model filarial nematode (Litomosoides sigmodontis). Strikingly, the 498 bovine proteins identified in nodule fluid were strongly dominated by antimicrobial proteins, especially cathelicidins. This first high-throughput analysis of an Onchocerca spp. proteome across the lifecycle highlights its profound complexity and emphasizes the extremely close relationship between O. ochengi and O. volvulus The insights presented here provide new candidates for vaccine development, drug targeting and diagnostic biomarkers.

Immunotherapy with mutated onchocystatin fails to enhance the efficacy of a sub-lethal oxytetracycline regimen against Onchocerca ochengi.

Human onchocerciasis (river blindness), caused by the filarial nematode Onchocerca volvulus, has been successfully controlled by a single drug, ivermectin, for over 25 years. Ivermectin prevents the disease symptoms of severe itching and visual impairment by killing the microfilarial stage, but does not eliminate the adult parasites, necessitating repeated annual treatments. Mass drug administration with ivermectin does not always break transmission in forest zones and is contraindicated in individuals heavily co-infected with Loa loa, while reports of reduced drug efficacy in Ghana and Cameroon may signal the development of resistance. An alternative treatment for onchocerciasis involves targeting the essential Wolbachia symbiont with tetracycline or its derivatives, which are adulticidal. However, implementation of antibiotic therapy has not occurred on a wide scale due to the prolonged treatment regimen required (several weeks). In the bovine Onchocerca ochengi system, it has been shown previously that prolonged oxytetracycline therapy increases eosinophil counts in intradermal nodules, which kill the adult worms by degranulating on their surface. Here, in an "immunochemotherapeutic" approach, we sought to enhance the efficacy of a short, sub-lethal antibiotic regimen against O. ochengi by prior immunotherapy targeting onchocystatin, an immunomodulatory protein located in the adult female worm cuticle. A key asparagine residue in onchocystatin was mutated to ablate immunomodulatory activity, which has been demonstrated previously to markedly improve the protective efficacy of this vaccine candidate when used as an immunoprophylactic. The immunochemotherapeutic regimen was compared with sub-lethal oxytetracycline therapy alone; onchocystatin immunotherapy alone; a gold-standard prolonged, intermittent oxytetracycline regimen; and no treatment (negative control) in naturally infected Cameroonian cattle. Readouts were collected over one year and comprised adult worm viability, dermal microfilarial density, anti-onchocystatin IgG in sera, and eosinophil counts in nodules. Only the gold-standard antibiotic regimen achieved significant killing of adult worms, a profound reduction in microfilarial load, and a sustained increase in local tissue eosinophilia. A small but statistically significant elevation in anti-onchocystatin IgG was observed for several weeks after immunisation in the immunotherapy-only group, but the antibody response in the immunochemotherapy group was more variable. At 12 weeks post-treatment, only a transient and non-significant increase in eosinophil counts was apparent in the immunochemotherapy group. We conclude that the addition of onchocystatin immunotherapy to a sub-lethal antibiotic regimen is insufficient to induce adulticidal activity, although with booster immunisations or the targeting of additional filarial immunomodulatory proteins, the efficacy of this strategy could be strengthened.

Onchocerciasis caused by Onchocerca lupi: an emerging zoonotic infection. Systematic review.

Globalization has increased circulation of people, their food, livestock and pets in the world, and changes in the environment, climate and human behaviour have led to the rapid expansion of emerging infections throughout the world. One of the reasons of a new pathogen affecting humans is the passage from an animal to a human being. Onchocerca (O.) lupi, a filarial worm first described in a wolf in 1967, is an emerging pathogen which has been incriminated as the etiological agent for 205 canine, 2 feline and 18 human infections in Europe, Tunisia, Turkey, Iran and the USA. Most frequent findings in animals and humans are monolateral or asymmetrical variably painful subconjunctival swellings and nodules containing immature or mature worms affecting the eye and/or adjacent tissues accompanied by conjunctival hyperemia. Occasionally, subcutaneous nodules and masses affecting the spinal cord have been observed in humans. Diagnosis of O. lupi is achieved by microscopy of excised adult female worms which exhibit a particular cuticular structure and molecular analysis. Treatment consists in worm removal accompanied by antihelminthic, antibiotic and anti-inflammatory therapy.

Clinical case presentation and a review of the literature of canine onchocercosis by Onchocerca lupi in the United States.

BACKGROUND: Onchocerca lupi, a filarioid of zoonotic concern, infects dogs and cats causing ocular lesions of different degrees, from minor to severe. However, infected animals do not always display overt clinical signs, rendering the diagnosis of the infection obscure to the majority of veterinarians. Canine onchocercosis has been reported in the Old World and the information on its occurrence in the United States, as well as its pathogenesis and clinical management is still meagre. This study reports on the largest case series of O. lupi infection from the United States and reviews previous cases of canine onchocercosis in this country. METHODS: Information on the clinical history of a series of eight cases of O. lupi infection in dogs diagnosed in Minnesota, New Mexico, Colorado and Florida, from 2011 to 2014, was obtained from clinical records provided the veterinary practitioners. Nematodes were morphologically identified at species level and genetically analyzed. RESULTS: All dogs displayed a similar clinical presentation, including subconjunctival and episcleral nodules, which were surgically removed. Each dog was subjected to post-operative therapy. Whitish filaria-like parasites were morphologically and molecularly identified as O. lupi. CONCLUSIONS: This study confirms that O. lupi is endemic in the United States, indicating that the distribution of the infection is probably wider than previously thought. With effect, further studies are urgently needed in order to improve the diagnosis and to assess the efficacy of therapeutic protocols, targeting the parasite itself and/or its endosymbionts.