Encephalitozoon cuniculi is a eukaryote, unicellular, spore-forming, obligate intracellular microorganism of the phylum Microsporidia, with domestic rabbits as its main host. Another important species in which this pathogen has been identified are humans, the infection being therefore called a ”zoonosis”. The transmission takes place via the horizontal route or the vertical route, and cell-mediated immunity plays the biggest role in the infected hosts’ protection. Encephalitozoonosis can manifest itself as an acute infection, with neurological signs, renal signs, and ocular lesions, or as a chronic or subclinical infection, which is usually the case for asymptomatic carriers. The diagnostic techniques usually carried out are histological examination, serological tests, and molecular genetic techniques. The treatment of encephalitozoonosis is usually symptomatic, with unrewarding results, and prevention methods include periodical serological screening, prophylactic administration of fenbendazole, and maintenance of a clean environment. The purpose of this article is to review the current data regarding the pathogenesis, host immunity, clinical signs, diagnostic methods, treatment, and prevention methods of encephalitozoonosis in the domestic rabbit, as well as to analyze the prevalence of this disease in different countries of the world.

Canine degenerative myelopathy (CDM) is a spontaneous neurodegenerative disease. Genetically, CDM is an autosomal recessive disease with incomplete penetrance, most commonly caused by a genetic mutation in exon 2 of gene SOD1 (c.118G > A). This study aimed to determine the mutant allele frequency associated with CDM in various dog breeds from Romania. Dogs (n = 230) from 26 breeds were included in the study. Genotyping using the PCR-RFLP technique was performed on DNA extracted from oral swabs. The results revealed that 204 dogs were homozygous for the wild-type allele (G/G), 16 were heterozygous (A/G), and 10 were homozygous for the mutant allele (A/A). The mutant allele was identified in Wire Fox Terrier, Romanian Mioritic Shepherd, German Shepherd, Rottweiler, Belgian Shepherd, and Czechoslovakian Wolfdog breeds. The mutant allele frequency (A) within the tested population was 0.0783. The results for Belgian Shepherd, German Shepherd, and Romanian Mioritic Shepherd were in Hardy–Weinberg equilibrium, but a departure was observed for Rottweiler. The current study included a first screening of the Romanian Bucovina Shepherd, Romanian Mioritic Shepherd, and Caucasian Shepherd breeds. Genetic testing for the mutation associated with CDM is important in order to avoid the risk of the emergence of dogs homozygous for the SOD1:c118G > A allele.

Encephalitozoon cuniculi infection in rabbits represents a true challenge in both diagnosis and treatment of the disease. This study aims to describe and analyze all methods of identifying the presence of the microsporidian in a rabbit through antemortem and postmortem methods. The patient manifested clinical signs of vestibular disease and mild renal symptoms with no significant improvement under treatment, which finally led to euthanasia. Serological and molecular tests confirmed positivity for E. cuniculi in serum and urine, feces, brain, kidney and urinary bladder, respectively. Histopathological findings showed suggestive inflammatory lesions of encephalitis and nephritis and no changes in the eye globe and liver, but with no identification of microsporidian spores. This is the first complete case report of E. cuniculi in a rabbit in Romania, as well as the first report of urinary bladder molecular testing with a positive result, which facilitates for further diagnosis exploration for rabbits.

Birds are inherently social creatures that rely on pairing to enhance their well-being. Since many bird species lack obvious physical differences between females and males, sex identification is essential for ensuring their welfare. Additionally, early determination of the sexes of birds is crucial for their breeders, especially considering that most companion birds do not display clear sexual characteristics. Molecular genetic sexing has been demonstrated to be the most reliable method for determining the sexes of monomorphic birds. The objective of the present study was to demonstrate rapid, effective, and precise identification of sex in birds through quantitative real-time PCR (qPCR) using samples obtained via a minimally invasive technique (oral swabs). This qPCR method assesses variations in gene copy numbers within conserved Z-specific genes such as CHRNA6, DDX4, VPS13A, LPAR1, and TMEM161B, which are absent from the W chromosome. A total of 34 samples were included in this study from the following 17 bird species: domestic pigeon (Columba livia domestica), domestic chicken (Gallus gallus domesticus), domestic goose (Anser anser f domesticus), domestic duck (Anas platyrhynchos domesticus), Mute swan (Cygnus olor), Budgerigar (Melopsittacus undulatus), Lovebird (Agapornis roseicollis), Cockatiel (Nymphicus hollandicus), Red-rumped parrot (Psephotus haematonotus), Rose-ringed parakeet (Psittacula krameri), African grey parrot (Psittacus erithacus), domestic Canary (Serinus canaria forma domestica), Goldfinch (Carduelis carduelis major), Gouldian Finch (Chloebia gouldiae), Red Siskin (Carduelis cucullata), Australian Zebra Finch (Taeniopygia castanotis), and Common buzzard (Buteo buteo). The results proved that the CHRNA6, DDX4, VPS13A, LPAR1, and TMEM161B genes can reveal the sexes in the Neognath birds tested.

Encephalitozoon cuniculi is a microsporidian, domestic rabbits being the main host. The disease can be acute or subclinical, but treatment options are limited and usually with unrewarding results; therefore, diagnosis and prevention of encephalitozoonosis in rabbits are of the utmost importance. This study aims to obtain the first preliminary information of the prevalence of E. cuniculi in the north-western region of Romania. A total of 176 rabbits were clinically examined and 2 mL of blood was sampled from each. An enzyme-linked immunosorbent assay (ELISA) kit by Medicago (Medicago, Uppsala, Sweden) on the resulted blood serum was utilized. Statistical analysis of the results was conducted using the EpiInfo 2000 software (CDC, Atlanta, GA, USA). A total prevalence of 39.2% (69/176) was identified, with statistically significant differences in relation to the rabbits’ clinical status, age, season of sampling, breeding system, body condition score and county of origin; the different family farms tested also had a statistically significant difference. This study gives the first preliminary information on this pathogen distribution on Romania’s territory, but further studies need to be performed on larger regions to declare the prevalence in the country.

Encephalitozoon cuniculi is a microsporidian widely spread in rabbits (Oryctolagus cuniculus) and other species, including humans, causative of neurological disorders or remaining in a latent state in the host organism. The aim of this study was to estimate the prevalence of E. cuniculi in rabbits located in the North-Western region of Romania, and to run a comparative diagnosis for E. cuniculi by multiple methods. A total of 381 rabbits were included, originating from households, family farms and wildlife, which were subjected to serological and/or molecular genetics diagnostic methods for E. cuniculi identification. Seropositivity of 43.02% (151/351) was obtained by ELISA, together with a 45.45% (110/242) prevalence from urine, feces and organs by nested PCR. Additionally, a prevalence of 48.39% (15/31) was identified by a comparative real-time PCR (qPCR). The urinary bladder is firstly reported for molecular E. cuniculi diagnosis, with a positivity of 30.56% (11/36) by nested PCR. Despite the disagreement between the diagnostic methods, the present results highlight the level of pathogen dissemination among rabbits in North-Western Romania that represents a risk for not only rabbits and other animals, but also for the general public by its zoonotic character.