First report of Giardia duodenalis in pet rabbits in Brazil

Giardia duodenalis is a flagellate protozoan that multiplies in the small intestine of a wide variety of hosts, animals and humans. It has a worldwide distribution, however it is considered a neglected disease by the World Health Organization (WHO). Nowadays, rabbits are being chosen as pets, especially by children. There are already reports of the occurrence of G. duodenalis in rabbits from other countries, but research has not been carried out in Brazil yet. Thus, the objective of our work was to verify the occurrence and molecularly characterize G. duodenalis that affect pet rabbits, through the polymerase chain reaction (PCR) in the northwest region of the state of São Paulo, Brazil. Fecal samples from 100 rabbits were collected, which later underwent a process of DNA extraction and amplification by nested-PCR (nPCR), using the SSU rRNA gene, and β-giardin (bg), glutamate dehydrogenase (gdh) and triosephosphate isomerase (tpi) to determine the assemblage. A questionnaire was answered by the owners with information about gender, age, deworming, diarrhea, water source, food, place of residence and contact with other animals. From those samples, 40 were positive for G. duodenalis. Good quality of the SSU rRNA gene by nPCR were obtained from two samples. For the first time, we report the occurrence of G. duodenalis assemblage A on pet rabbits in Brazil.

Sensitive, quantitative detection of Besnoitia darlingi and related parasites in intermediate hosts and to assess felids as definitive hosts for known and as-yet undescribed related parasite species

Besnoitia darlingi, B. neotomofelis and B. oryctofelisi are closely related coccidian parasites with cats as definitive hosts. While B. darlingi uses opossums as intermediate hosts, B. neotomofelis and B. oryctofelisi have been described in Southern Plains woodrats (Neotoma micropus) from the USA and in domestic rabbits from Argentina, respectively. A comparison of the Internal Transcribed Spacer-1 (ITS-1) region of the ribosomal DNA (rDNA) of these Besnoitia spp. showed only a few differences. The present study aimed at developing a real-time PCR to detect B. darlingi, B. neotomofelis and B. oryctofelisi in tissues of intermediate and in faeces of definitive hosts in order to support studies of these organisms’ epidemiology and pathogenesis.

The established PCR was based on primer regions distinct from the ITS-1 sequences of ungulate Besnoitia spp. and made use of a Besnoitia universal probe. To monitor inhibition, a heterologous internal control was established based on the enhanced green fluorescent protein gene. The real-time PCR reacted with B. darlingi, B. neotomofelis and B. oryctofelisi, while the novel PCR did not recognize ungulate Besnoitia spp. (B. besnoiti, B. bennetti, B. tarandi). DNA of Apicomplexa ascribed to other Besnoitia-related genera, including other gut parasites of cats (Cryptosporidium parvum, Giardia duodenalis, Tritrichomonas foetus), was not recognized. The real-time PCR had an analytic sensitivity of less than 1 tachyzoite per reaction. In feline faeces spiked with B. darlingi oocysts, the limit of detection was a DNA amount equivalent to 1 oocyst per PCR reaction. In B. darlingi infected ɣ-interferon knock-out mice, the lung was identified as the predilection organ. In conclusion, this real-time PCR should advance further studies on these parasites and may inspire research on related species, not only in the Americas, but also in other parts of the world.

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A quantitative real-time PCR was established to detect Besnoitia darlingi.

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Analytical sensitivity of the real-time PCR for tachyzoites and oocysts was high.

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Lung tissue was the predilection site for B. darlingi in ɣ-interferon knockout mice.

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Related parasites like B. neotomofelis and B. oryctofelisi are detected by this PCR, too.

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PCR holds promise to assess the epidemiology of B. darlingi and related species.

PROGNOSTIC INDICATORS FOR SURVIVAL OF ORPHANED NEONATAL AND JUVENILE EASTERN COTTONTAIL RABBITS (SYLVILAGUS FLORIDANUS): 1,256 CASES (2012-17)

Orphaned eastern cottontail rabbits (ECRs; Sylvilagus floridanus) often present to wildlife clinics within their geographic range and require considerable dedication of time and resources. The objective of this analytical cross-sectional study was to assess initial examination findings to be used as prognostic indicators for orphaned neonatal and juvenile ECRs. The medical records of the University of Illinois Wildlife Medical Clinic were searched for ECRs presenting between 2012 and 2018. This criterion identified 1,256 ECRs that were then classified as survivors (survived and released) or as nonsurvivors (euthanized or natural death) within 72 h of admission. Presenting weight, body system abnormalities, hydration status, intervention prior to presentation, and singleton versus group presentation were categorically recorded for each individual ECR. The data were modeled using a series of logistic regression models fitted using the general linear model. Individuals were significantly more likely to be nonsurvivors if they presented as singletons (P<0.0001), presented with moderate/severe (P<0.001) or mild integumentary signs (P=0.0261), presented with multi-organ disease (P<0.001), presented with neurologic signs (P<0.0003), or had treatment provided prior to presentation (P=0.031). Factors that did not predict survival status in ECRs included body weight (P=0.210), presence of respiratory signs (P=0.674), and presence of dehydration (P=0.356). These findings may be used at wildlife medical clinics to make triage criteria for euthanasia as well as dedicate limited funds and labor to cases with the best prognosis for survival.

Complete mitochondrial genome of the Arctic hare, Lepus arcticus

In this study, we report on the complete mitochondrial genome of the Arctic hare, Lepus arcticus (Leporidae; Lagomorpha) a large lagomorph endemic to the northernmost regions of Greenland. The complete mitogenome of L. arcticus was 16,972 bp long and was typical of genus Lepus mitogenomes in genomic content and structure, as the entire mitogenome contained 13 protein-coding genes (PCGs), two ribosomal RNA (rRNA) genes, 22 transfer RNA (tRNA) genes, and one control region. The phylogenetic analysis of the Arctic hare within Leporidae confirmed the sister relationship among Lepus species. This mitogenome sequence will provide a useful resource for investigations of biogeography, phylogenetic distance, and evolutionary history in lagomorphs.

Rabbit Whole Embryo Culture

The rabbit is a mainstay of regulatory developmental toxicity testing; however, due to the historic absence of experimental tools for this species, there is a dearth of information about its fundamental embryology and the mechanisms underlying developmental toxicity. Relatively recently, there have been advances in the methods of rabbit whole embryo culture (WEC), and this has prompted an increase in understanding of rabbit embryogenesis. Described herein are the methods used to remove early somite-stage embryos (gestation day 9) and sustain their growth for 48 h. Although there are similarities to the well-described rodent WEC, there are also important differences. Akin to rodent WEC, the major phases of organogenesis can be investigated, including neural tube development, cardiac looping, segmentation, and the development of the anlagen of the optic and otic regions, craniofacial development, somites, and early limb bud development. Unlike the rodent, rabbit WEC requires the use of an apparatus that allows for the continuous gassing of embryos, and one may observe the expansion and closure of the visceral yolk sac around the embryo. After completion of the culture period, embryos are examined across several growth and developmental parameters including a quantitative morphological scoring system. Embryonic growth and development in the absence of maternal influences allows for the study of the direct action of agents or their metabolites on the embryo. The use of both rodent and rabbit WEC together is a powerful strategy with which to investigate species-specific vulnerabilities to specific agents.

Identification of a Bitter-Taste Receptor Gene Repertoire in Different Lagomorphs Species

The repertoires of bitter-taste receptor (T2R) gene have been described for several animal species, but these data are still scarce for Lagomorphs. The aim of the present work is to identify potential repertoires of T2R in several Lagomorph species, covering a wide geographical distribution. We studied these genes in Lepus timidus, L. europaeus, Oryctolagus cuniculus algirus, Romerolagus diazi, and Sylvilagus floridanus, using O. cuniculus cuniculus as control species for PCR and DNA sequencing. We studied the identities of the DNA sequences and built the corresponding phylogenetic tree. Sequencing was successful for both subspecies of O. cuniculus for all T2R genes studied, for five genes in Lepus, and for three genes in R. diazi and S. floridanus. We describe for the first time the partial repertoires of T2R genes for Lagomorphs species, other than the common rabbit. Our phylogenetic analyses indicate that sequence proximity levels follow the established taxonomic classification.

Food competition between a large ruminant and a small hindgut fermentor: the case of the roe deer and mountain hare

In this study, we demonstrate that the mountain hare and roe deer compete with each other. This was determined using "natural experiments" of populations found in sympatry and allopatry on the islands along the west coast of Norway. We demonstrate that both species occupy the same habitats, share the same food resources and that food availability is limited. Two browsing species as different in size as roe deer and mountain hare might be expected to partition the available vegetation (e.g. woody scrub) in terms of height above ground level. However, from the evidence collected, the feeding-height-separation hypothesis must be rejected as an explanation for ecological separation between roe deer and mountain hares because there was extensive height overlap in resource utilisation by both species and neither species changed its feeding height in response to the presence of the other. Total browse utilisation did not increase when both species were together; rather, species-specific browse utilisation declined when the other species was present. However, the foraging behaviour of each herbivore varied significantly between the allopatric and sympatric sites. When both herbivores were present, the clip diameter of shoots browsed by mountain hares declined to match those selected by roe deer, while roe deer switched from a browse-dominated diet to a diet dominated by winter-green gramineae. The change to smaller-diameter shoots likely resulted in the hare increasing its intake of digestion-inhibiting or toxic secondary metabolites, while the alternative choice of digging through the snow like roe deer to reach the winter-green gramineae is a practice considered energetically too costly for hares. On this basis, we conclude that the enforced switch to a nutritionally inferior diet by mountain hares at the sympatric sites may result in changes to growth rate and body size which consequently impact on mortality and may explain the competitive superiority of the roe deer.