Mean Intensity Of Infection Research Articles

Study of haemoflagellates Trypanosoma sp. infection in some fish of Iraq marshes and relationship of leukocytes with inflammatory response

Fresh water fishes infected with different species of genus Trypanosoma parasite that is similar to that same genus in blood of mammals. Trypanosomiasis or sleeping sickness disease that causes by protozoa flagellate parasites which live inside cell called Trypanosoma. Fish parasites play an important role in regulating the population of their hosts. This study was implemented to verify the infection with Trypanosoma sp. report the cellular intervening through inflammatory response in blood smears of infected fishes. A total of 190 fishes of three species Carasobarbus luteus, Aspius vorax and Liza abu were collected from Al-Hamare and Al-Chibayish marsh south of Iraq. The flagellate parasite Trypanosoma sp. observed in blood of Carasobarbus luteus 41.42% and Aspius vorax 12.28% fishes, while no infection was recorded with Trypanosoma sp. in Liza abu fishes. Prevalence and mean intensity of infection were calculated. The different counts and various types of inflammatory cells were monitored, there are increased in lymphocytes in the infected fishes. Statistically, there are significant differences (p<0.05) among species of infected fish with Trypanosoma sp.

Prevalence of Eimeria infection and risk factors associated with domestic chickens raised in Nsukka LGA, Enugu State, Southeast Nigeria

Eimeria infection has been considered the most important protozoan infection of the poultry industry in Nigeria because of its high incidence. A total of 400 faecal samples were collected from 10 farms in Nsukka LGA and analyzed using the Wisconsin’s faecal floatation technique. Data on the management practices of these farms were collected using a wellstructured questionnaire. Eimeria tenella was the only identified species. A total of 158 (39.5%) of the domestic chickens sampled were infected with the protozoan parasite. There was significant difference (p &lt; 0.0001) of E. tenella between towns and between the studied farms. Of the 5 towns sampled, the prevalence was highest at Obukpa town 52 (65.0%) and in birds aged 7 weeks 20 (83.3%) and least at Edem 2 (2.5%) and in birds aged 32 weeks 2 (5.0%). The mean intensity of infection was highest at Obukpa (9.35 ± 9.24) and in birds aged 4weeks (11.50 ± 11.09) and least in Edem town and in birds aged 32 weeks. The difference in prevalence between birds of different ages was significant (p &lt;0.0001). Majority of the farms practiced deep litter housing compared to battery cage users (90% vs. 10%). The most used vaccine was combination 7 (70%). Fifty percent of the farms employed the expertise of veterinary doctors in vaccine administration. Eimeria infection, the main cause of coccidiosis in chicken, has continued to be a major challenge in poultry production and management. Conclusively, the prevalence of Eimeria infection is moderately low as a result of the widespread use of vaccines and anticoccidials.

ASSESSMENT OF FASCIOLA GIGANTICA INFECTION IN THE LIVER OF CATTLE SLAUGHTERED IN IKPOBA/OKHA AREA COUNCIL, EDO STATE, NIGERIA

This study investigated the prevalence and intensity of Fasciola gigantica infection in the liver of cattle slaughtered in three abattoirs located in Ikpoba/Okha Local Government Area of Edo State, Nigeria. It also estimated the economic implications of the condemned liver. A total of 17,325 cattle were examined in the three abattoirs over a period of 252 days (approximately 69 cattle/day) spanning over the wet and dry seasons; 1,683 cattle were infected with an overall prevalence of 9.71%. In Abattoir A, 11774 cattle were examined with 1069 (9.08%) prevalence. In Abattoirs B and C, 4352 and 1199 cattle, respectively, were examined and 563 (12.94%) and 51 (4.25%) were respectively infected. From the three abattoirs, 155 (0.89%) livers were considered unfit for human consumption due to F. gigantica infection. For the wet season, 1062 (10.89%) cattle livers were infected while 621 (8.20%) were infected during the dry season. The mean intensity of infection during the wet season was 37.80 and 30.42 during the dry season. The financial loss due to infected liver condemnation was at N803,160 (1,947.050USD) showing that liver condemnation arising from F. gigantica infection is a major cause of financial loss to cattle farmers and dealers. There is, therefore, need for adequate veterinary inspections for early detection and treatment of the disease. There should be more meat inspection, especially in private/individual abattoirs.

A case report and statewide surveillance of “weak meat” condition of Alaska weathervane scallops, Patinopecten caurinus, linked to a recently identified pathogenic parasite, Merocystis kathae (Apicomplexa: Aggregatidae)

Weathervane scallop, Patinopecten caurinus, the largest scallop species in the world, is distributed from northern California, U.S.A., to the Bering Sea, and is only commercially harvested in Alaska. The fishery is considered well managed by the State of Alaska (U.S.A) Department of Fish and Game (ADF&G) and federal government, with many precautionary measures in place to avoid overharvest. There have been episodic declines in some management areas due to unknown causes. Fishermen also encounter scallops with abnormal adductor muscles, a condition colloquially termed “weak meat”, characterized by the retention of muscle when shucked, an obvious darkened discoloration, and/or an abnormal texture making the product unacceptable for marketing. A similar syndrome in Atlantic sea scallops, Placopecten magellanicus, described as “gray meat”, occurs in the eastern U.S. and Canada, and proposed causes include senescence, loss of bioenergetics due to chronic infestations, or a synergism of these factors. Recently a severe apicomplexan infection was found to cause a gray meat condition in Iceland scallops, Chlamys islandica, and the collapse of that stock. This parasite was subsequently detected in Atlantic sea scallops with the gray meat condition off the U.S. East Coast. Studies that followed identified the parasite as Merocystis kathae, previously described from the common whelk, Buccinum undatum, more than 100 years ago. In 2015 Bering Sea fishermen reported weak meat in their catch, so samples were submitted to ADF&G for diagnosis. Adductor muscles from all affected scallops had many large foci of an apicomplexan associated with necrosis, fibrosis, and muscular atrophy. Given the reduced quality, marketability, and possibly fitness of affected scallops, we performed a survey to estimate prevalence, intensity, and geographic distribution of this apicomplexan in Alaskan weathervane scallops. We sampled 180 scallops, from individual beds within each of the three major geographically broad scallop areas in Alaska. Overall prevalence was about 82%, ranging from 69 to 100% by district. Overall mean infection intensity, based on the number of parasite foci/section, was about 9 (range of 5–29, by location), with scallops from the Bering Sea and Southwest Kodiak being most severely infected. Molecular analyses confirmed that the Alaskan parasite is M. kathae, i.e., the same apicomplexan that caused the collapse of Icelandic scallops and a suspected cause for gray meat and mass mortality of Atlantic sea scallops in northeast North America.

Functional immunogenetic variation, rather than local adaptation, predicts ectoparasite infection intensity in a model fish species.

Natural host populations differ in their susceptibility to infection by parasites, and these intrapopulation differences are still an incompletely understood component of host‐parasite dynamics. In this study, we used controlled infection experiments with wild‐caught guppies (Poecilia reticulata) and their ectoparasite Gyrodactylus turnbulli to investigate the roles of local adaptation and host genetic composition (immunogenetic and neutral) in explaining differences in susceptibility to infection. We found differences between our four study host populations that were consistent between two parasite source populations, with no indication of local adaptation by either host or parasite at two tested spatial scales. Greater values of host population genetic variability metrics broadly aligned with lower population mean infection intensity, with the best alignments associated with major histocompatibility complex (MHC) “supertypes”. Controlling for intrapopulation differences and potential inbreeding variance, we found a significant negative relationship between individual‐level functional MHC variability and infection: fish carrying more MHC supertypes experienced infections of lower severity, with limited evidence for supertype‐specific effects. We conclude that population‐level differences in host infection susceptibility probably reflect variation in parasite selective pressure and/or host evolutionary potential, underpinned by functional immunogenetic variation.

Assessing early child development and its association with stunting and schistosome infections in rural Zimbabwean children using the Griffiths Scales of Child Development.

There is a paucity of reference early childhood development (ECD) data at community level in rural Africa. Our objective was to conduct a comprehensive assessment of ECD in rural Zimbabwe and determine the impact of stunting and schistosome infections on ECD. Using the Griffiths Scales of Child Development, we conducted a cross sectional assessment of Eye and Hand Coordination (EHC), Personal-Social-Emotional (PSE), Language and Communication (LC), Foundations of Learning (FL) and Gross Motor (GM) domains and the summary General Development (GD) in 166 children aged 6–72 months. The effects of stunting, malnutrition and Schistosoma haematobium infection on ECD was determined. The impact of praziquantel curative treatment of schistosome infection on the developmental scores was determined through a longitudinal follow up at 6 and 12 months. From an initial 166 children, 11 were found to have developmental deficits warranting further investigation. Of the remaining 155, 58.7% recorded a good (≥ average) score for the overall General Development (GD). Proportions of children scoring above the cut-off (≥ average) for each domain were GM (84.5%), PSE (80.6%), EHC (61.9%), FL (43.9%) and LC (44.5%). The prevalence of stunting was 26.8% (95% CI = 20.1%–34.8%) Scores for stunted children were significantly lower for EHC (p = 0.0042), GM (p = 0.0099), and GD (p = 0.0014) with the fraction of lower scores attributable to stunting being GM = 63.4%, GD = 46.6%, EHC = 45%, and LC = 21%. S. haematobium infection prevalence was 39.7% and mean infection intensity was 5.4 eggs/10 ml urine. Infected children had poorer cognitive performance scores for the FL (p = 0.0005) with 30.8% of poor FL attributable to the infection. Performance in all domains improved to the expected normal or above reference levels at 6 and 12 months post curative treatment of schistosome infections. Our study documented reference values for ECD in rural Zimbabwean children. The study detected deficiencies in the FL domain, which were more pronounced in children, infected with schistosomes, highlighting the need for provision of cognitive stimulation tools and access to early childhood foundation education. There is also need for improved child nutrition and treatment of schistosome infections to improve child development outcomes.

Analysis on the relationship between winter precipitation and the annual variation of horse stomach fly community in arid desert steppe, Northwest China (2007-2019).

Gasterophilus spp. have been found to be widespread in reintroduced Przewalski's horses in the Kalamaili Nature Reserve (Northwest China). However, data on the annual variation in Gasterophilus infections are lacking. To analyze the epidemiological features and determine the cause of the annual variation in Gasterophilus infections, we treated 110 Przewalski's horses with ivermectin and collected Gasterophilus larvae from fecal samples each winter from 2007 to 2019. All 110 Przewalski's horses studied were found to be infected by Gasterophilus spp., and a total of 141 379 larvae were collected. Six species of Gasterophilus were identified with the following prevalence: G. pecorum (100%), G. nasalis (96.36%), G. nigricornis (94.55%), G. haemorrhoidalis (56.36%), G. intestinalis (59.09%), and G. inermis (3.64%). The mean infection intensity of Gasterophilus spp. larvae in Przewalski's horses was 1285 ± 653. G. pecorum (92.96% ± 6.71%) was the most abundant species. The intensity of Gasterophilus spp. (r = –0.561, P < 0.046) was significantly correlated with winter precipitation. Our findings confirmed that, in the Kalamaili Nature Reserve, gasterophilosis is a severe parasitic disease in Przewalski's horses. Winter precipitation at the beginning of the year can indirectly affect the intensity and composition of Gasterophilus spp. in Przewalski's horses at the end of the year. Therefore, the water‐related ecological regulation should be carried out to help reduce the parasite infection of Przewalski's horses.

Studies on trematode metacercariae infecting libellulid larvae from the Western Ghats, Wayanad region.

Understanding the host specificity of trematode larvae is vital in predicting the mode of trophic level transfer of trematode parasites and their evolution. In this study, six species of trematode metacercariae, Eumegacetes sp., Orthetrotrema monostomum, Ganeo tigrinus, Mehraorchis sp., Pleurogenoides sp. and Phyllodistomum sp. infecting the larvae of the odonate family Libellulidae from the water bodies in the Wayanad region of the Western Ghats are recorded. The prevalence of infection of these metacercariae was 5.8%, 2.0%, 10.4%, 9.1%, 2.6% & 1.3%, respectively. Further, the mean intensity of infection was estimated to be 4.44, 1.67, 5.38, 6.21, 6.0 & 17.5 and the mean abundance 0.26, 0.03, 0.56, 0.56, 0.16 & 0.23 respectively.

Current status of helminthiases in Thailand: A cross-sectional, nationwide survey, 2019

Helminthiases are common neglected tropical diseases in Thailand, thus regular surveillance is necessary for their control. During fiscal year 2019, the Thailand Ministry of Public Health carried out a cross-sectional nationwide survey in people of all age groups from the 12 Regional Health Offices in 76 provinces of Thailand. Multi-stage cluster random sampling design was employed to assess the prevalence of helminth infections and certain behavioural risk factors. A total of 16,187 stool samples and demographic data were obtained from the participants. Stool examination was done and parasite eggs/lavae were identified microscopically by experienced technicians. Positive stool samples for Opisthorchis viverrini, hookworms, or Ascaris lumbricoides were further quantified and expressed in eggs per gram feces (EPG). The results revealed an overall prevalence of helminthic infections of 9.79% with over 14 species identified. The highest prevalence was hookworms (4.47%) followed by O. viverrini (2.2%) with mean infection intensities of 222.7 EPG and 120.9, respectively. The majority of the infections were low intensity (97.4% for hookworms and 99.1% for O. viverrini). Similarly for A. lumbricoides, 93.9% of the positive cases were low infections. Two major helminthiases caused by hookworms and O. viverrini were highlighted in this report. While the liver fluke was highly endemic in Northeast Thailand, the hookworms were prevalent in the southmost region of the country. Association with demographic characteristics and risk behaviors of the two parasites were analyzed and presented in this study. Overall, this countrywide survey provides basic information of the current status of helminth infections in Thailand. Moreover, the data clearly indicates a dramatic reduction of O. viverrini prevalence likely due to extensive control activities under the national campaign against the liver fluke over the past five years.

Detection of Trichinella murrelli and Trichinella pseudospiralis in bobcats (Lynx rufus) from Oklahoma

Trichinella spp. infect wild carnivores throughout the world. We determined the prevalence and mean infection intensity of Trichinella spp. in bobcats (Lynx rufus) from 41 counties in Oklahoma (USA). Tongues from 306 bobcats were examined using artificial tissue digestion. The prevalence (95% confidence interval) of Trichinella spp. was 5.9% (3.7%-9.2%) in which 18 of the 301 bobcats were infected. Bobcats infected with Trichinella spp. were detected in 10 of the 41 (24.4%; 13.7%-39.5%) counties sampled. Although variable, a statistically significant difference was not detected in the prevalence of Trichinella spp. among counties where bobcats were collected. The mean (standard deviation) and median (range) infection intensity of Trichinella sp. larvae were 30.9 (39.8) and 9.6 (0.6-119.9) larvae per gram of tissue examined. Genotyping results demonstrated that 17 bobcats were infected with T. murrelliand one bobcat was infected with T. pseudospiralis. This is the first report of T. pseudospiralis in bobcats and in Oklahoma. These data suggest the bobcat, as an obligate carnivore, is likely an important host in maintaining T. murrelli sylvatic cycles in Oklahoma.

Nicienie i kokcydia gołębi bytujących na wybranych zabytkach w Szczecinie

City pigeons (Columba livia forma urbana) are an integral part of the urbanized environment. However, they host parasites that can be passed zoonotically to humans and to domestic and wild birds. The aim of the study was to establish the current prevalence of nematode and coccidians infestation among city pigeons roosting in old buildings in Szczecin. The pigeon kits, comprising city pigeons and stray breeding pigeons which had not returned to their lofts, numbered from 45 to 60 individuals. Samples of pigeon droppings were tested qualitatively by the flotation method and then quantitatively by the McMaster technique. Oocyst culture was also performed in a humid chamber at a temperature of 24–26° C. The oocytes were identified using standard keys. Two roundworm families were identified, Ascaridia spp. (two species) and Capillaria spp., and three coccidian species: Eimeria labbeana, E.columbarum and E. columbae. Overall, the extent of infection was approximately 100% throughout the study area, but varied depending on the place of origin of the material. The prevalence of worms with eggs ranged from 9% to 16% for Ascaris spp. and 24–41% for Capillaria spp. The maximum OPG values, i.e. the number of oocytes per gram of faeces, were 360 for Ascaris spp. and 1134 for Capillaria spp; these indicate the intensity of infection. The most frequently observed species was Eimeria labbeana, whose prevalence was found to range from 82% to 96% depending on location, with a mean infection intensity of 1130–1870 OPG. The prevalence of the other two Eimeria species was also high, with respectively values of 56–77% for E. columbarum and 32–43% for E. columbae, depending on the location. The mean OPG values for the species were 430–1770 and 29–52, respectively. Maximum OPG values were 223,000 for E. labbeana, 54,000 for E. columbarum and 830 for E. columbae.

Nematodes of Amphisbaena vermicularis Wagler, 1824 (Squamata, Amphisbaenidae) from Brazilian Atlantic Forest remnants

ABSTRACT Knowledge about parasitic fauna provides valuable information on natural history, health, and conservation of the hosts. In this study, we present the parasitological descriptors (prevalence, mean intensity and mean abundance of infection) of the nematodes of Amphisbaena vermicularis, a poorly studied amphisbaenian. We analysed 33 adult specimens (22 males and 11 females) from three Atlantic Forest remnants in the Northeast region of Brazil, characterised by a gradient of anthropogenic disturbance. We recovered 244 nematodes in the intestines of 17 (51.5%) animals: 225 Maracaya graciai (Atractidae) prevalence 42.4%, mean abundance 6.81 ± 3.16, mean intensity 16 ± 6.81 (range 1–100), and 19 Aplectana sp. (Cosmocercidae) prevalence 9.1%, mean abundance of infection 0.57 ± 0.37, mean intensity of infection 6 ± 2.60 (range 2–11). There was no statistically significant difference in the mean intensity of M. graciai infection in relation to the study areas and the sex of the animals. Maracaya graciai was found in all study sites regardless of the level of anthropogenic disturbance, while Aplectana sp. was present only in the most conserved forest remnant or with mid-level disturbance, with higher parasitological indices in the conserved remnant. Therefore, further studies should be carried out to verify the usefulness of Aplectana sp. as an indicator of environmental health and anthropogenic impact. The current study records a new host of M. graciai and Aplectana sp. and also extends the geographical distribution of M. graciai.

Haemogregarine of Genus Dactylosoma (Adeleorina: Dactylosomatidae) in Species of Rhinella (Anura: Bufonidae) from the Brazilian Amazon.

The present study aims to record the occurrence of a haemogregarine of the genus Dactylosoma in anurans in the eastern Brazilian Amazon. Specimens of Leptodactylus macrosternum, Rhinella major, and Rhinella marina were collected in the municipality of Santarém, west of the State of Pará, in Brazil. Parasitic forms identified as Dactylosoma sp. were recorded by light microscopy, with magnification of 400 and 1000 X. Aspects about the morphology and morphometry of Dactylosoma sp. are presented. The mean intensity of infection was 200,000 parasites/mL in R. major and 50,000 parasites/mL in R. marina. The present study expands the occurrence of parasites of the genus Dactylosoma in Brazil, presenting a new anuran host for this parasite in the Brazilian Amazon region.

Prevalence and intensity of gastrointestinal nematode infection in domestic horses (Equus Caballus) in the Sudano-Guinean Altitude Zone of the North West Region of Cameroon

A study was conducted from &nbsp;March to September 2020 in five Sub-Divisions in Donga Mantung to determine the prevalence and &nbsp;intensity of gastrointestinal (GI) nematode infection of domestic horses with the objective to develop and implement strategic parasitic control measures. &nbsp;A total of 794 randomly selected horses (317 males and 477 females), aged ≤1 to ≥7 years old were examined using standard parasitological procedure. Fresh fecal samples were collected from the rectum and examined coprologicaly in the laboratory for the presence of GI nematode eggs. A qualitative flotation &nbsp;technic using saturated sodium chloride solution and a quantitative technic using the Mc Master Slide method of coprological analysis were realized. Result indicated &nbsp;nine species of nematodes (Strongylus equinus, Parascaris equorum, Oxyuris equi, Habronema muscae, Strongyloides westeri, Trichostrongylus axei, Trichonema sp, Triodontophorus serratus and Dictyocaulus aenfieldi) were identified. Horses harbored one or more nematode infection with a total prevalence rate of 100% for the gastrointestinal nematodes. The two genera of nematodes commonly encounter during the study period were Strongylus equinus type of egg (97,0% ) and Parascaris equorum (52,0%) in horses. There was a significant difference (P&lt;0.05) in prevalence of Strongyle type of eggs and P. equorum between species.&nbsp; The mean intensity of infection was 1459 ± 956 in horses with age 3 years. Poly-parasitic infections with prevalence of 98,0% were more common &nbsp;than mono-parasitic infections of 2,0%. These results suggest the possible need of studying the epidemiology, economic impact of these nematodes affecting the equine industry, stimulating important aspects to livestock programs and prevention activities.

Estimating true prevalence of Schistosoma mansoni from population summary measures based on the Kato-Katz diagnostic technique.

BackgroundThe prevalence of Schistosoma mansoni infection is usually assessed by the Kato-Katz diagnostic technique. However, Kato-Katz thick smears have low sensitivity, especially for light infections. Egg count models fitted on individual level data can adjust for the infection intensity-dependent sensitivity and estimate the ‘true’ prevalence in a population. However, application of these models is complex and there is a need for adjustments that can be done without modeling expertise. This study provides estimates of the ‘true’ S. mansoni prevalence from population summary measures of observed prevalence and infection intensity using extensive simulations parametrized with data from different settings in sub-Saharan Africa.MethodologyAn individual-level egg count model was applied to Kato-Katz data to determine the S. mansoni infection intensity-dependent sensitivity for various sampling schemes. Observations in populations with varying forces of transmission were simulated, using standard assumptions about the distribution of worms and their mating behavior. Summary measures such as the geometric mean infection, arithmetic mean infection, and the observed prevalence of the simulations were calculated, and parametric statistical models fitted to the summary measures for each sampling scheme. For validation, the simulation-based estimates are compared with an observational dataset not used to inform the simulation.Principal findingsOverall, the sensitivity of Kato-Katz in a population varies according to the mean infection intensity. Using a parametric model, which takes into account different sampling schemes varying from single Kato-Katz to triplicate slides over three days, both geometric and arithmetic mean infection intensities improve estimation of sensitivity. The relation between observed and ‘true’ prevalence is remarkably linear and triplicate slides per day on three consecutive days ensure close to perfect sensitivity.Conclusions/significanceEstimation of ‘true’ S. mansoni prevalence is improved when taking into account geometric or arithmetic mean infection intensity in a population. We supply parametric functions and corresponding estimates of their parameters to calculate the ‘true’ prevalence for sampling schemes up to 3 days with triplicate Kato-Katz thick smears per day that allow estimation of the ‘true’ prevalence.

High Prevalence and Intensity of Trichinella Infection in Yukon American Black (Ursus americanus) and Grizzly (Ursus arctos) Bears.

Trichinella spp. nematodes are commonly found in bear species (Ursidae) and can pose severe health risks to humans when infective first-stage larvae are ingested in meat. Samples of tongue or masseter muscle from 22 male and 11 female American black bears (Ursus americanus; mean age 6.5 yr, range 1-16 yr) and 22 male, eight female, and one unknown sex grizzly bears (Ursus arctos; mean age 8.8 yr, range 2-28 yr), from Yukon, Canada, were tested to determine prevalence and intensity of Trichinella spp. infection. For black bears, prevalence was 20% and mean intensity was 401 larvae per gram of tissue (LPG), whereas for grizzly bears, prevalence was 71%, and mean infection intensity was 35 LPG. Isolates from all positive samples were identified as genotype Trichinella-T6 by multiplex PCR. For black bears, prevalence is the highest reported in Canada and infection intensity the highest recorded in North America. One black bear had a larval burden of 1,173 LPG, the second highest recorded in any host species. The prevalence in grizzly bears was the highest reported in Canada for this host. In total, 90% (27 of 30) of infected bears had infection burdens above the human food safety threshold of ≥1 LPG, reinforcing the importance of communicating the health risks to people consuming bear meat.

High prevalence, intensity, and genetic diversity of Trichinella spp. in wolverine (Gulo gulo) from Yukon, Canada

BackgroundSpecies of Trichinella are globally important foodborne parasites infecting a number of domestic and wild vertebrates, including humans. Free-ranging carnivores can act as sentinel species for detection of Trichinella spp. Knowledge of the epidemiology of these parasites may help prevent Trichinella spp. infections in northern Canadian animals and people. Previous research on Trichinella spp. in wildlife from Yukon did not identify risk factors associated with infection, or the diversity and identity of species of Trichinella in regional circulation, based on geographically extensive sampling with large sample sizes.MethodsIn a cross-sectional study, we determined the prevalence, infection intensity, risk factors, and species or genotypes of Trichinella in wolverine (Gulo gulo) in two regions of Yukon, Canada, from 2013–2017. A double separatory funnel digestion method followed by mutiplex PCR and PCR-RFLP were used to recover and identify species of Trichinella, respectively.ResultsWe found larvae of Trichinella in the tongues of 78% (95% CI 73–82) of 338 wolverine sampled. The odds of adult (≥ 2 years) and yearling (1 year) wolverine being Trichinella spp.-positive were four and two times higher, respectively, compared to juveniles (<1 year). The odds of Trichinella spp. presence were three times higher in wolverine from southeast than northwest Yukon. The mean intensity of infection was 22.6 ± 39 (SD, range 0.1–295) larvae per gram. Trichinella T6 was the predominant genotype (76%), followed by T. nativa (8%); mixed infections with Trichinella T6 and T. nativa (12%) were observed. In addition, T. spiralis was detected in one wolverine. Out of 22 isolates initially identified as T. nativa in multiplex PCR, 14 were analyzed by PCR-RFLP to distinguish them from T. chanchalensis, a recently discovered cryptic species, which cannot be distinguished from the T. nativa on multiplex PCR. Ten isolates were identified either as T. chanchalensis alone (n = 7), or mixed infection with T. chanchalensis and T. nativa (n = 2) or T. chanchalensis and Trichinella T6 (n = 1)].ConclusionsWolverine hosted high prevalence, high larval intensity, and multiple species of Trichinella, likely due to their scavenging habits, apex position in the food chain, and wide home range. Wolverine (especially adult males) should be considered as a sentinel species for surveys for Trichinella spp. across their distributional range.Graphical

Reliability metrics and their management implications for open pond algae cultivation

The prevalence of contaminating organisms in outdoor algae cultivation, with the often-associated dramatic crop failures, necessitates the need for metrics describing production system reliability. Standard metrics for algae cultivation reliability are critically needed to be able to map improvements in operational parameters, but do not currently exist. In this work, we present a set of standard metrics including mean time to failure (MTTF) and mean time between failures (MTBF) as the basis for the calculation of pond failure rate (FR) and reliability coefficient (RC). Metrics associated with the numbers of contaminating organisms such as abundance ratio (AR), prevalence of infection (PI), and mean intensity of infection (MII) are also relevant. These metrics, based on measured experimental values of outdoor pond performance during the Algae Testbed Public-Private Partnership (ATP3) Unified Field Studies (UFS), provide a basis for quantifying pond failure and provide insight into potential pond management and contaminant mitigation strategies. From these reliability metrics applied to this dataset, we are able to link operational parameters, such as harvest frequency and inoculum source, to pond reliability for different algae strains and seasons, and from an assessment of AR, provide contamination thresholds beyond which a culture may be unrecoverable. Ultimately, the implementation of widely-practiced and simple-to-calculate algae pond reliability metrics calculated from rapid and easy to collect data or observations will reduce risk and uncertainty in large-scale algae deployment and aid in the development of integrated pest management (IPM) strategies.

First Record of Clinostomum sp. (Digenea: Clinostomidae) in Danio rerio (Actinopterygii: Cyprinidae) and the Implication of Using Zebrafish from Pet Stores on Research.

Many scientific studies still use zebrafish from pet stores as animal models, even cutting-edge researches. However, these animals differ genotypically and phenotypically between them. The importance of the use of standardized models is widely recognized. Besides that, another consequence of using zebrafish from unknown origins is the acquisition of parasitized animals. This study aimed to relate the infection by Clinostomum sp. in zebrafish. Animals sold as "high standard" were acquired from a commercial company. Swimming alterations and superficial yellow dots were observed in five zebrafish with clinical signs, which were isolated, euthanized, and necropsied. Muscular yellow cysts with metacercaria associated with lesions were observed. The muscular cysts were responsible for the superficial yellow dots as well as the swimming alterations. The prevalence was 2.5%, and the mean infection intensity was 7 digeneans/host. The cysts measured a mean of 1251.43 μm long × 784.28 μm wide. Metacercariae measured a mean of 4847 μm long × 1353 μm wide. This first report about infection by Clinostomum sp. in zebrafish is globally relevant since the host and the parasite genus currently overlap worldwide. Furthermore, this study sheds light on the importance of the specific pathogen-free commercial creations or laboratory-reared zebrafish for research.

Host diversity, phylogenetic relationships and local environmental factors drive infection patterns of a non-native parasite in tropical floodplain fish assemblages

Biodiversity, biological traits of potential host species, and environmental conditions may mediate the emergence of new diseases. We assessed the relative influence of such factors on patterns of infection by Austrodiplostomum compactum (Digenea, Diplostomidae) in fish assemblages of the Upper Parana River floodplain, Brazil. Multiple infection parameters were modeled at the community and species levels using phylogenetic diversity (PD), abundance (total and for a main reservoir species Plagioscion squamosissimus), local environmental conditions and phylogenetic distance from P. squamosissimus (Dis_Plag). In total, 108 fish species were collected and 28 were infected. At the community level, mean parasite abundance and mean infection intensity were positively associated with PD and the interaction between PD and environmental conditions, whereas host richness was negatively associated with PD. The complementary results indicate a biodiversity sampling effect rather than dilution effect. Environmental conditions often had the strongest coefficients in community-level models and mediated associations between infection parameters and other factors. At the species level, consistent negative associations between infection parameters and Dis_Plag indicate phylogenetic niche conservatism of parasites. Integration of community and species-level analyses demonstrates that phylogenetic diversity can affect host–parasite interactions in multiple ways, but that the associations depend on phylogenetic relationships and environmental conditions.