The public health and clinical significance of Giardia and Cryptosporidium in domestic animals

Giardia and Cryptosporidium are common enteric parasites of domestic animals, particularly dogs, cats and livestock. Their occurrence is of potential significance from both clinical and public health perspectives yet, until recently, confusion over the taxonomy of these organisms prevented a clear understanding of the epidemiology of infections with both Giardia and Cryptosporidium. The recent application of molecular epidemiological tools has helped to resolve taxonomic issues, allowing cycles of transmission to be determined. In addition, advances have been made in elucidating mechanisms associated with pathogenesis, whereas only limited progress has been achieved in the areas of chemotherapy and prophylaxis.     

The relationship of soil province to molecular characterization and phylogenetic analysis of Cryptosporidium parvum isolated from calves in Georgia

Although Cryptosporidium spp. are found throughout the world and in multiple environmental conditions, few data are available that explore the possibility of an association between specific environmental parameters and the species or strain of Cryptosporidium. This study examines the potential association between a particular Cryptosporidium species/strain found in calves and soil provinces in Georgia, USA. Necropsy cases spanning the years 1996-2002 were tested. No significant differences (P=0.962, chi(2) test of homogeneity) between numbers of positive cases were noted among soil provinces. Phylogenetic analysis of the sequences for the PCR products revealed sequence similarity of the products with Cryptosporidium parvum strain C1. Although, clinical Cryptosporidiosis in calves was not found to be affected by soil province and may be caused by a single genotype, other genotypes may be responsible for subclinical infection and warrant further investigation.     

Genotypic analysis of Giardia duodenalis in domestic cats

BACKGROUND: Giardia duodenalis is an intestinal flagellated protozoan that affects many mammalian species often causing severe diarrheal disease. Several different genotypes have been identified (Assemblages A-G). Most isolates recovered from domestic cats have been assigned to either Assemblage A, the zoonotic form of the parasite, or Assemblage F, identified thus far only in cats. Genotypic variation within G. duodenalis may influence clinical presentation and course of disease. Therefore, host-adapted genotypes may not be responsible for diarrheal disease (eg, Assemblage F in cats). HYPOTHESIS: Multiple Giardia genotypes will be present in domestic cats, including Assemblage F, which will not be correlated with clinical signs. ANIMALS: 250 domestic cats from eastern Mississippi and northwestern Alabama. METHODS: Prevalence survey. Fecal samples evaluated for cysts using a centrifugation concentration technique and a commercially available direct immunoflourescent antibody kit. Giardia isolates were characterized by PCR amplification and sequencing of the glutamate dehydrogenase gene. RESULTS: Both Assemblage A-I (6/17) and Assemblage F (11/17) were identified. Although Assemblage was significantly associated with age and housing, no association was detected between Assemblage and a variety of other factors including the presence of gastrointestinal signs (acute vomiting, diarrhea, and constipation). CONCLUSIONS AND CLINICAL IMPORTANCE: The presence of diarrhea in domestic cats with Giardia cannot be used as a predictor of the presence of zoonotic genotypes in animals within the study area. Although Assemblage A was associated with age and housing, veterinarians should consider any isolation of Giardia from domestic cats as potentially zoonotic.     

秦岭大熊猫槽盘吸虫的鉴定与遗传进化分析

本研究旨在对采自大熊猫秦岭亚种(ailuropoda melanoleuca qinlingensis)小肠内的槽盘吸虫进行种类鉴定及遗传进化分析。通过形态学和分子生物学方法,对虫体样本分别进行染色显微镜观察和核糖体DNA内转录间隔区Ⅱ(ITS2)部分序列的PCR扩增和序列分析。经不同染色方法比较后,发现孔雀绿染色法处理后的虫体外部形态以及内部结构清晰,形态上符合印度槽盘吸虫(Ogmocotyle indica)的典型特征;序列及遗传进化分析表明,10个样本ITS2序列完全一致,其系统发生树显示10个样本与O.indica位于同一分枝。研究结果表明,分离的虫株从形态学和进化分析上均与印度槽盘吸虫具有高度一致性,提示该槽盘吸虫为印度槽盘吸虫。     

Genotyping of Cryptosporidium spp. from free-living wild birds from Brazil

In wild and domestic birds, cryptosporidiosis is often associated with infections by Cryptosporidium galli, Cryptosporidium baileyi and Cryptosporidium meleagridis. In addition to these species, a number of avian Cryptosporidium species yet to be fully characterized are commonly found among exotic and wild avian isolates. The present study aimed to detect and identify samples of Cryptosporidium spp. from free-living wild birds, in order to contribute to the knowledge of the variability of this parasite in the free-living population of Brazil. Stool samples were collected from 242 birds, with the following proportions of individuals: 50 Emberizidae (20.7%), 112 Psittacidae (46.3%), 44 Cardinalidae (18.2%), 12 Turdidae (5.0%), eight Ramphastidae (3.3%), seven Icteridae (2.9%), three Estrilididae (1.2%), two Contigidae (0.8%), two Thraupidae (0.8%) and two Fringilidae (0.8%). Among the 242 fecal samples from wild birds, 16 (6.6%) were positive for the presence of oocysts of Cryptosporidium. Molecular characterization of the 16 samples of Cryptosporidium, were performed with phylogenetic reconstructions employing 292 positions of 18S rDNA. None of the samples of birds was characterized as C. meleagridis. C. galli was identified in one rufous-bellied thrush (Turdus rufiventris), five green-winged saltators (Saltator similis), one slate-coloured seedeater (Sporophila schistacea), one goldfinch (Carduelis carduelis) and three saffron finches (Sicalis flaveola). One goldfinch isolate, one buffy-fronted seedeater (Sporophila frontalis), one red-cowled cardinal (Paroaria dominicana) and one other saffron finch (S. flaveola) were identified as C. baileyi. Avian genotype II was found in an isolate from a white-eyed parakeet (Aratinga leucophthalma). Clinical symptoms of cryptosporidiosis in birds have already been described and the number of wild birds which were shedding parasites was high. Therefore, further epidemiological research and disease surveillance of birds in the wild is warranted.     

猪源隐孢子虫Hsp70基因的测定与种系发育关系分析

从河南两个地区猪的粪便中分离纯化了猪源隐孢子虫卵囊。参考隐孢子虫Hsp70基因属特异性引物,用PCR分别扩增了卵囊基因组DNA大小均为1 948 bp的片段,PCR产物经电泳鉴定后用试剂盒回收纯化,纯化后PCR产物直接测序。将测得的序列和推测出的氨基酸序列分别用ClustalX软件与已报道的相应序列比对,用DNASTAR中的MegAlign分析其同源性,并用PAUP绘制系统发育进化树。序列分析结果显示河南猪源隐孢子虫两个分离株Hsp70 DNA序列的同源性为99.9%,与其他隐孢子虫相应序列同源性介于81.9%~99.8%之间,其中与猪隐孢子虫(Cryptosporidium suis,AF221533)同源性最高分别为99.8%,97.9%;与安氏隐孢子虫(C.andersoni,AY954592)同源性最低。两个分离株推导Hsp70氨基酸序列的同源性为100%,同其他隐孢子虫相关序列的同源性在92.8%~99.8%之间。本研究为隐孢子虫诊断及流行病学研究打下了良好基础。     

Pesticides and domestic animals.

Domestic animals are quite often poisoned by pesticides despite the considerable effort made through legislation and Ministry recommendations to provide adequate safeguards for the use of agricultural chemicals. All pesticides have to be registered and recommendations and restrictions for use are printed on the labels. But a number of cases involving the misuse of certain poisons as bait for vermin has caused concern recently to both Government and industry. Special problems face the veterinary surgeon who has to treat a pet animal with suspected esticide poisoning. This paper provides possible sources of information from which the veterinary surgeon may obtain help with diagnosis, advice on treatment and laboratory aid.     

Ixodes (Afrixodes) drakensbergensis n. sp. from domestic and wild animals in Natal, Republic of South Africa.

Ixodes (Afrixodes) drakensbergensis n. sp., is described from females, males, nymphs and larvae collected on a drag at Giant's Castle Nature Reserve, Natal, Republic of South Africa; it was also taken from an eland in the same area and from goats and a cow in the adjacent Tank Area 118. The occurrence of I. (A.) drakensbergensis on domestic animals suggests that it may be of economic importance in this area. Information is provided to separate the new species from other closely related Ixodes species that occur or may occur in this region.     

Detection of Cryptosporidium muris type oocysts from beef cattle in a farm and from domestic and wild animals in and around the farm

Cryptosporidium muris type oocysts were detected from 21 of 516 beef cattle in a farm. Then we surveyed Cryptosporidium oocysts in 348 beef and dairy cattle, 500 pigs, 101 dogs, 38 wild animals and 11 zoo-kept animals in and around the farm. Oocysts were detected from only 2 of 25 Japanese field mice, Apodemus speciosus in the same farm. Gene analysis suggested that the oocysts were different from the C. muris type bovine isolate.     

Molecular characterization of Hepatozoon sp. from Brazilian dogs and its phylogenetic relationship with other Hepatozoon spp

To characterize phylogenetically the species which causes canine hepatozoonosis at two rural areas of Rio de Janeiro State, Brazil, we used universal or Hepatozoon spp. primer sets for the 18S SSU rRNA coding region. DNA extracts were obtained from blood samples of thirteen dogs naturally infected, from four experimentally infected, and from five puppies infected by vertical transmission from a dam, that was experimentally infected. DNA of sporozoites of Hepatozoon americanum was used as positive control. The amplification of DNA extracts from blood of dogs infected with sporozoites of Hepatozoon spp. was observed in the presence of primers to 18S SSU rRNA gene of Hepatozoon spp., whereas DNA of H. americanum sporozoites was amplified in the presence of either universal or Hepatozoon spp.-specific primer sets; the amplified products were approximately 600bp in size. Cloned PCR products obtained from DNA extracts of blood from two dogs experimentally infected with Hepatozoon sp. were sequenced. The consensus sequence, derived from six sequence data sets, were blasted against sequences of 18S SSU rRNA of Hepatozoon spp. available at GenBank and aligned to homologous sequences to perform the phylogenetic analysis. This analysis clearly showed that our sequence clustered, independently of H. americanum sequences, within a group comprising other Hepatozoon canis sequences. Our results confirmed the hypothesis that the agent causing hepatozoonosis in the areas studied in Brazil is H. canis, supporting previous reports that were based on morphological and morphometric analyses.     

Hemoprotozoa of domestic animals in France: Prevalence and molecular characterization

Very limited information is available on epizootiology of haematozoan infections in French domestic animals. In an attempt to address this issue, prevalence of piroplasmida was studied in carnivores and ruminants, whereas prevalence of Hepatozoon spp. was only investigated in carnivores. In total, 383 animals were included in the survey (namely 116 cats, 108 dogs, 91 sheep and 68 cows). Parasite diagnosis was carried out using molecular methods such as PCR and sequencing of the 18S rRNA gene. In addition, ruminant samples were analyzed with the reverse line blotting technique (RLB). Results of RLB and PCR plus sequencing were in total agreement.     

Cryptosporidium scrofarum n. sp. (Apicomplexa: Cryptosporidiidae) in domestic pigs (Sus scrofa)

We describe the morphological, biological, and molecular characteristics of Cryptosporidium pig genotype II and propose the species name Cryptosporidium scrofarum n. sp. to reflect its prevalence in adult pigs worldwide. Oocysts of C. scrofarum are morphologically indistinguishable from C. parvum, measuring 4.81–5.96 μm (mean = 5.16) × 4.23–5.29 μm (mean = 4.83) with a length to width ratio of 1.07 ± 0.06 (n = 400). Oocysts of C. scrofarum obtained from a naturally infected pig were infectious for 8-week-old pigs but not 4-week-old pigs. The prepatent period in 8-week-old Cryptosporidium-naive pigs was 4–6 days and the patent period was longer than 30 days. The infection intensity of C. scrofarum in pigs was generally low, in the range 250–4000 oocysts per gram of feces. Infected pigs showed no clinical signs of cryptosporidiosis and no pathology was detected. Cryptosporidium scrofarum was not infectious for adult SCID mice, adult BALB/c mice, Mongolian gerbils (Meriones unguiculatus), southern multimammate mice (Mastomys coucha), yellow-necked mice (Apodemus flavicollis), or guinea pigs (Cavia porcellus). Phylogenetic analyses based on small subunit rRNA, actin, and heat shock protein 70 gene sequences revealed that C. scrofarum is genetically distinct from all known Cryptosporidium species.     

Genotypic characterisation of Giardia from domestic dogs in the USA

The first large-scale urban survey of Giardia infections in dogs was undertaken in the USA. It involved several locations in the Western United States with Giardia isolates from microscopy-positive samples characterised by multi-locus PCR and sequencing. A high prevalence of Giardia was confirmed in asymptomatic domestic dogs, and for the first time, provides evidence that zoonotic assemblages/subgroups of Giardia occur frequently in domestic dogs living in urban environments, and more frequently than the dog specific assemblages.     

Dermatophytes isolated from domestic and feral animals

In work over a period of 8 years, dermatophytes were recovered from 12 animal species in the North Island of New Zealand. A total of 552 dermatophytes were isolated and belonged to the Microsporum (6 species) and Trichophyton (6 species) genera.

Some unusual isolations are reported: Microsporum canis and Trichophyton mentagrophytes var. mentagrophytes were recovered from calves; Microsporum distortum from a dog, which was the first known isolation from an animal in the North Island; four horses, from the same stable, yielded Microsporum equinum which has not previously been recorded in this country; Trichophyton erinacei was recovered from lesions on a cat which is the first report of the dermatophyte from an animal other than the dog, hedgehog or man; Trichophyton equinum var. autotrophicum was a rare isolation from a dog.

Species affinity was demonstrated with the dermatophytes M. canis; M. nanum; M. equinum; T. equinum; and T. verrucosum. These zoophilic species appear to be passed between individuals of the same species, with occasional infection in man and other animal species. T. mentagrophytes var. mentagrophytes had a wider distribution, being isolated from dogs, cats, guinea-pigs and rats. The infection in rats was subclinical.

The geophilic species M. cookei, T. ajelloiand and T. terrestre were recorded but not regarded as being pathogenic. M. gypseum was significant in cases involving dogs, horses and a cat, as arthrospores were seen invading the affected hairs.     

Genetic and phylogenetic analysis of glycoprotein of rabies virus isolated from several species in Brazil

Genetic and phylogenetic analyses of the region containing the glycoprotein (G) gene, which is related to pathogenicity and antigenicity, and the G-L intergenic region were carried out in 14 Brazilian rabies virus isolates. The isolates were classified as dog-related rabies virus (DRRV) or vampire bat-related rabies virus (VRRV), by nucleoprotein (N) analysis. The nucleotide and amino acid (AA) homologies of the area containing the G protein gene and G-L intergenic region were generally lower than those of the ectodomain. In both regions, nucleotide and deduced AA homologies were lower among VRRVs than among DRRVs. There were AA differences between DRRV and VRRV at 3 antigenic sites and epitopes (IIa, WB+ and III), suggesting that DRRV and VRRV can be distinguished by differences of antigenicity. In a comparison of phylogenetic trees between the ectodomain and the area containing the G protein gene and G-L intergenic region, the branching patterns of the chiropteran and carnivoran rabies virus groups differed, whereas there were clear similarities in patterns within the DRRV and VRRV groups. Additionally, the VRRV isolates were more closely related to chiropteran strains isolated from Latin America than to Brazilian DRRV. These results indicate that Brazilian rabies virus isolates can be classified as DRRV or VRRV by analysis of the G gene and the G-L intergenic region, as well as by N gene analysis.     

Isolation of dermatophytes from domestic animals in Norway

The examination of 2066 skin scrapings from domestic animals in the period from July 1981 to June 1984, revealed dermatophytes in 439 samples. Dermatophytes isolated were: M. canis in dog, cat, cattle, horse, swine, goat, rabbit and hamster, M. equinum in dog and horse, M. gypseum in horse, T. equinum in horse and cattle, T. mentagrophytes in dog, cat, cattle, horse, guinea pig and rabbit, T. verrucosum in cattle and E. floccosum in dog.     

Natural Besnoitia sp. infection in domestic rabbits from Argentina

Besnoitia sp. are apicomplexan coccidian parasites affecting several species of mammals and cold-blooded animals in several countries. Besnoitia sp. tissue cysts were seen in several tissues of five rabbits from a rabbit breeder in La Plata, Argentina. Bradyzoites released from macroscopic tissue cysts were inoculated onto bovine monocytes, and into interferon gamma gene knockout (KO) mice. Besnoitia sp. tachyzoites were seen in the peritoneal exudate of KO mice on day 10 pi and these tachyzoites were infective to other KO mice. Tachyzoites grown in cell culture were infective to gerbils (Meriones unguiculatus). This is the first report of Besnoitia sp. infection in any host in Argentina.