Bronchoalveolar lavage in an immunosuppressed rabbit model of invasive pulmonary aspergillosis

A rabbit model of invasive aspergillosis has been used to investigate the pathogenesis of Aspergillus infection in the immunosuppressed host. The animals received hydrocortisone daily and a single dose of cyclophosphamide 2 days prior to intratracheal instillation of conidia from Aspergillus fumigatus. Bronchoalveolar lavage (BAL) was performed in 3 infected and 2 control saline treated animals sacrificed on days 1, 2, 4, 7 and 10 following inoculation. Infective load within the lung was quantified using an assay for chitin which is an important component of fungal cell walls (in particular the hyphal cell wall) and is not present in vertebrate tissue. The total BAL white cell count did not discriminate between infected and saline treated animals and Aspergillus was cultured from one lavage specimen only. Infected animals developed a marked neutrophil alveolitis by day 2 in contrast to a near total absence of neutrophils in the lavages of the control animals. Phagocytosis of conidia by alveolar macrophages was prominent but did not prevent progressive infection as confirmed by measurement of lung chitin. This pattern of cellular response within the alveolar airspace reflects the complex nature of the response to Aspergillus infection in the immunosuppressed host.     

Role of antibodies and effect of BCG vaccination in experimental candidiasis in mice

The role of humoral antibodies and the effect of BCG vaccination were studied in the experimental candidiasis in mice. The antibody suppressed, B-cell deficient animals were prepared by repeated administration of rabbit anti-mouse--antiserum to the new born mice from birth onwards. Such immunodeficient animals along with controls were infected intravenously with Candida albicans, to study the course of candidal infection. It was observed that B-cell-deficient animals were found to be more susceptible to candidal infection than the controls, as indicated by their steady loss of body weight, longer mean time to death and higher viable counts of candidal cells in different organs. The anti-candidal antibodies were absent in all B-cell-deficient animals but present in the controls. These results suggest that antibodies make a contribution in protection against candidal infection in mice. The BCG vaccinated animals were prepared by repeated intravenous administration of BCG to mice and these vaccinated animals along with unvaccinated controls were challenged intravenously with C. albicans, to study the course of candidal infection. It was observed that BCG vaccination prolonged meantime to death and reduced the number of candidal cells in their kidneys.     

Cohabitation of a <Emphasis Type="Italic">Brucella melitensis</Emphasis> infected Alpine ibex (<Emphasis Type="Italic">Capra ibex</Emphasis>) with domestic small ruminants in an enclosure in Gran Paradiso National Park,in Western Italian Alps

After the first report of Brucella melitensis infection from a 7-year-old alpine ibex (Capra ibex) buck living in Gran Paradiso National Park (GPNP), further studies demonstrated the presence of the infection in ibex and chamois. Considering that livestock herds keep on sharing pastures with more than 3,500 ibex and 9,000 chamois in the park, our aim was to demonstrate under controlled conditions the possibility of Brucella infection passing from wild ruminants to livestock. A 7-year-old male alpine ibex with clinical signs of brucellosis and serologically positive was released in a 5,000 m² enclosure together with five goats and two sheep rams. Due to poor condition, ibex was suppressed at day 40, domestic ruminants stayed into the enclosure potentially contaminated by ibex for further 38 days. During this period, we had monitored our animals taking blood from domestic ruminants every 15 days and tested the serum to Rose Bengal agglutination test and Complement Fixation test. Domestic animals tested negative at serology at all sampling time and at isolation, while B. melitensis biovar 3 was isolated from ibex tissues. Our data show that transmission of infection from ibex to livestock is not easy. After 40 days of strict cohabitation and 38 days of permanence in an area where an infected ibex lives, no one of the domestic animals contracted infection. In spite of the limitation of our field trial, we have demonstrated that long direct and indirect contact between alpine ibex and domestic animals will not easily lead to an infection of the latter. Further investigations are needed to confirm our results and evaluate the effective risk of B. melitensis transmission from alpine ibex to livestock.     

Outbreak of Mycobacterium marinum infection among captive snakes and bullfrogs

Since 1985 mycobacterial infection has been observed occasionally among snakes and bullfrogs housed in the Wisconsin exhibit at the Milwaukee Zoo. Prospective screening of animals was initiated in September 1990, after two cases occurred in March and June 1990. Overall, of 47 animals that were housed in the exhibit from 1981 through its closure in 1995, 15 (31.9%) were diagnosed with mycobacterial infection. That includes 10 cases (of 24 animals; 40% prevalence) that occurred during the final 5 years, when all animals were actively being screened for infection. Infection was documented by culture for seven animals, histology for four animals, and both histology and culture for four animals. Species determination of nine of the 10 isolates revealed Mycobacterium marinum. Genetic fingerprinting of the eight available isolates using pulsed field gel electrophoresis (PFGE) showed that six animals (five snakes and one bullfrog) were infected with the same strain of M. marinum (strain A) and two snakes were infected with a second strain (strain B). Deaths of animals infected with strain A spanned 1992–1995, and for strain B 1990–1992. It is postulated that possible routes of transmission were inhalation of infected aerosols or ingestion of contaminated food, water, or fomites. These data suggest that in closed systems the presence of mycobacterial infection in one animal significantly increases the risk of infection for all animals. Moreover, individual pathogenic strains may persist for prolonged periods of time. Zoo Biol 21:233–241, 2002. © 2002 Wiley‐Liss, Inc.     

Immunosuppression in experimental cryptococcosis in rats: Modification of macrophage functions by T suppressor cells

The influence of lymphocytes on the modulation of macrophage functions in altered immune states induced by Cryptococcus neoformans infection in rats has been investigated. In this report we observed a decrease of in vitro phagocytic activity by peritoneal cells (PC) from rats that received T suppressor cells induced by cryptococcal infection, against both the same microorganism that stimulated this suppressor population (p<0.05) and another non-pathogenic primary yeast (Candida tropicalis), (p<0.02). The microbicide function of the PC from these animals present a significant decrease in challenge by C. tropicalis (p<0.002) when compared with PC from animals transferred with T normal cells. The transference of T suppressor cells induced by cryptococcal infection in animals immunized with human serum albumin-complete Freund's adjuvant (HSA-CFA) produces a significant alteration of the phagocytosis to HSA-human red cells (HSA-HRC) when compared with the phagocytosis observed in animals that received T normal cells or the phagocytosis of normal animals (p<0.001). We could also observe that the DTH to HSA studied during 30 days was negative in rats transferred with PC sensitizated with HSA and treated with suppressor T cells, when compared with the DTH response of animals transferred with PC-HSA cocultured with normal cells (p<0.05 21st day). The data presented in this paper illustrated that following infection of rats with C. neoformans there is a change in some population of accessory cells behavior reflected by the modification of several functions, such as phagocytosis, lytic activity and antigen presentation.     

Use of a fluorescent stain for evaluating in vitro infection with Leishmania panamensis

Understanding the mechanisms responsible for mediating the effects of stress on Trypanosoma cruzi infection is crucial for determining the full impact of stress on Chagas’ disease and for devising effective interventions. Dehydroepiandrosterone (DHEA), a steroid hormone synthesized from pregnenolone, is secreted by the adrenal cortex in response to stress. Although its physiologic role has not been fully defined, DHEA has been shown to modulate immune function. In the present study, we evaluated the levels of corticosterone and the ability of T. cruzi infection to modulate the expression of Th2 cytokines in Wistar rats with chronic Chagas’ disease submitted to repetitive stress. The animals submitted to stress displayed enhanced levels of corticosterone as compared to control counterparts. Stress and infection triggered the most elevated concentrations of corticosterone. DHEA significantly reduced corticosterone levels for infected and stressed animals with DHEA. The infected animals displayed enhanced levels of IL-10 and IL-4 as compared to control ones. Stress combined with infection triggered the higher levels of IL-10 and IL-4. DHEA alone and combined with infection and stress significantly increased IL-10 and IL-4 levels. Then, this study might provide additional clues about factors that regulate some of the immunoregulatory aspects of T. cruzi infection and might offer new opportunities for therapeutic interventions.     

Effect of cyclophosphamide on rats experimentally infected with Cryptococcus neoformans

This study was undertaken to establish the function of T-lymphocytes in protective immunity against a cryptococcal infection in animals treated with Cyclophosphamide (Cy) pre or post infection and to determine how they relate to the progression of the disease.Inbred Suquía rats were infected either intranasally (i.n.) or intraperitoneally (i.p.) with 10⁵ viable Cryptococcus neoformans cells. The infected rats were divided in three groups. One of the groups (group I) was utilized as a control. The second group (group II) was treated with Cy 3 days before the infection. The third group (group III) was treated with Cy 3 days after the infection.At approximately 22 days post infection, C. neoformans growth in selected organs of all animals were determined. In addition, humoral and delayed-type hypersensitivity (DTH) response were assayed in the rats.When the Cy was applied after the infection the DTH was significantly diminished and inverse to the colony forming unit (CFU) which increased leading to the animals death. On the other hand, injection of the drug 3 days before infection did not modify the response, that was comparable in both treated and the control animals.In this study it were found haemagglutinating antibodies in sera from i.n. and i.p. infected rats although at minimal levels and were not present in all animals.The results show that with a low T-cell function induced as a consequence of injecting Cy after the infection, rats did not develop a normal DTH response to cryptococcal infections and were not able to control a cryptococcal infection as well as animals with normal T-cell function.     

Seroprevalence of Toxoplasma gondii in wild boars (Sus scrofa leucomystax) and wild sika deer (Cervus nippon) in Gunma Prefecture, Japan

The ingestion of undercooked meat from wild animals can be a source of Toxoplasma gondii infection in humans and other animals. In this study, we determined the seroprevalence of T. gondii infection in 175 wild boars (Sus scrofa leucomystax) and 107 wild sika deer (Cervus nippon) hunted in 2004–2007 in Gunma Prefecture, Japan, by using a commercial latex agglutination test (LAT). Antibodies (LAT, 1:64 or higher) to T. gondii were found in 6.3% of wild boars and 1.9% of sika deer. This is the first record of T. gondii infection in wild deer in Japan, and deer and wild boar meat should be cooked well before human consumption.     

Systemic candidiasis in mice immunized with Candida albicans ribosomes

In view of our previous findings that vaccination of mice with Candida albicans ribosomes protects them against experimental systemic candidiasis, the aim of this study was to investigate the effect of this vaccination on the course of infection in immunized animals. Since the kidney is the maj or target in systemic candidal infection, we concentrated in this research on studying the histopathology and determining quantitatively the candidal colonization of this organ. The experiments were carried out at various time intervals after intravenous inoculation with live C. albicans. The colonization of kidneys in immunized mice was markedly lower than that in controls. The maximal difference in renal colonization between immunized and non immunized animals was observed when relatively low challenge doses were used. The inhibition of candidal multiplication in immunized mice seemed to be correlated to their increased resistance against lethal challenge, as expressed by a significantly higher survival rate. Histopathological changes and fungal elements were found in kidneys of control mice as early as 20 h post infection, while the kidneys of immunized mice did not seem affected by the disease. Moreover, even 3 days post infection, the kidneys of vaccinated animals still seemed normal. In conclusion, apparently the ribosomal vaccination leads to diminished colonization of the major site of infection in candidiasis, thus affording protection to the immunized animals against these infections.     

Paracoccidioidomycosis in nude mice: Presence of filamentous forms of the fungus

Congenitally athymic nude mice (nu/nu) and their phenotypically normal littermates (nu/+) were intraperitoneally infected with yeast cells of a strain of Paracoccidioides brasiliensis. The nude mice developed a severe and generalized infection with an intense parasitism of several organs, accompanied by a low-grade of tissue reaction. The lesions were characterized by abundant yeast-like cells of the fungus, and in some animals, numerous hyphal forms could be well visualized. In control animals, infection was moderate, almost exclusively restricted to the area of inoculation, and the lesions presented few parasites surrounded by an inflammatory response. Filamentous forms of the fungus were never encountered in these animals.     

Predilection Muscles and Physical Condition of Raccoon Dogs (Nyctereutes procyonoides) Experimentally Infected with Trichinella spiralis and Trichinella nativa

The predilection muscles of Trichinella spiralis and T. nativa were studied in 2 experimental groups of 6 raccoon dogs (Nyctereutes procyonoides), the third group serving as a control for clinical signs. The infection dose for both parasites was 1 larva/g body weight. After 12 weeks, the animals were euthanized and 13 sampling sites were analysed by the digestion method. Larvae were found in all sampled skeleton muscles of the infected animals, but not in the specimens from the heart or intestinal musculature. Both parasite species reproduced equally well in the raccoon dog. The median density of infection in positive tissues was 353 larvae per gram (lpg) with T. spiralis and 343 lpg with T. nativa. All the infected animals had the highest larvae numbers in the carpal flexors (M. flexor carpi ulnaris). Also tongue and eye muscles had high infection levels. There were no significant differences in the predilection sites between these 2 parasite species. Trichinellosis increased the relative amount of fat, but not the body weight in the captive raccoon dogs. Thus, Trichinella as a muscle parasite might have catabolic effect on these animals.     

Prion permissive pathways: extracellular matrix genes control susceptibility to prion infection

There are wide variations in the susceptibility of humans, animals, and cultured cell lines to infection by prions. In this issue of The EMBO Journal, Marbiah et al ( 2014 ) identified a gene regulatory network that regulates the susceptibility of cultured cells to prion infection. Surprisingly, a number of these genes impact the structure of the extracellular matrix. These results have important implications for understanding mechanisms of prion infection and also suggest new therapeutic targets.     

Laboratory rearing of <Emphasis Type="Italic">Theileria annulata</Emphasis>-free <Emphasis Type="Italic">Hyalomma anatolicum anatolicum</Emphasis> ticks

Hyalomma anatolicum anatolicum is a three-host tick which transmits Theileria annulata infection in Indian cattle. Laboratory rearing of ixodid ticks is an essential requirement of any laboratory engaged with research on ticks and tick borne diseases. The Entomology laboratory of Indian Veterinary Research Institute is fully equipped with all the facilities and skilled manpower to maintain a homogenous H. a. anatolicum population throughout the year. The continuous supply of eggs, larvae and adults of H. a. anatolicum is maintained to meet out the demand of different experiments viz., preparation of tick antigens for immunization of animals, experimental challenge, isolation of genomic DNA and RNA. Maintenance of a H. a. anatolicum colony free of T. annulata infection is imperative for the experimental challenge infestation on cross-bred (Bos indicus × B. taurus) calves, in order to prevent the transmission of T. annulata infection to the experimental animals. A system has been developed in the laboratory in which the larvae of H. a. anatolicum were fed on New Zealand white rabbits and the dropped fed nymphs molted to adults are fed on cross-bred calves free of T. annulata infection. This synthetic cycle prevents the transstadial transmission of T. annulata as the rabbits are unsusceptible to T. annulata infection and only the adults were fed on cross-bred animals. Moreover, absence of transovarial transmission of T. annulata prevents the chance of carry over infection to experimental animals in the next cycle. Declaration: The experiments have been conducted in accordance with the approved guidelines of Committee for the Purpose of Control and Supervision of Experimentation on Animals (CPCSEA). Besides, the institute animal ethics committee continuously monitored the animal experimentation.     

Gastric mucosal changes induced by long term infection with Helicobacter pylori in Mongolian gerbils: effects of bacteria eradication

Helicobacter pylori infection has been reported to induce various mucosal changes, including gastric adenocarcinoma, in Mongolian gerbils 62 weeks after inoculation. Using Mongolian gerbils, this study examined whether or not eradication of the bacteria with drugs at specified times after infection prevents the development of mucosal changes. After orally inoculating with H. pylori (TN2GF4, vacA- and cagA-positive), the animals were killed 18 months later. Four or 8 months after H. pylori inoculation, eradication was performed by concurrent treatment with omeprazole+clarithromycin. Immediately after treatment ended, in both the 5 and 9 month groups, it was verified that H. pylori was completely eradicated. Autopsy performed 18 months after H. pylori inoculation revealed gastric hyperplastic polyps with erosive lesions and ulcers that were grossly visible in the non-treated control group. In addition, atrophic gastritis, intestinal metaplasia, carcinoids, and adenocarcinomas were histologically observed in the animals. In animals eradicated after 4 months and autopsied after 18 months, however, such mucosal changes were not observed. In contrast, intestinal metaplasia and mucosal atrophy was observed in animals eradicated after 8 months and autopsied after 18 months. It was concluded that early eradication of H. pylori infection with drug therapy can prevent severe gastric mucosal changes, to include adenocarcinomas, in Mongolian gerbils.     

A Long-Term Study of <Emphasis Type="Italic">Neospora caninum</Emphasis> Infection in a Swedish Dairy Herd

A longitudinal study was performed in a Swedish dairy herd where Neospora caninum had been isolated from a stillborn calf. Starting in autumn 1994, blood samples from all female animals in the herd were collected once yearly until 1999. The sera were analysed for presence of IgG₁ antibodies to N. caninum by the iscom ELISA, and by an avidity ELISA to establish the timing of infection. In addition, data on reproductive performance were compiled. During the study the percentage of seropositive female animals increased from 63% to 87%. In 1994 a large number of young animals tested seropositive although their dams were seronegative, indicating that a transmission of the parasite other than the vertical had recently occurred. Low avidity values supported this assumption. The annual abortion rate increased from a mean of 2% before the initiation of the study to 9% in 1994–1998. During the same time, as judged by the avidity data, a large proportion of the animals shifted from being recently to being chronically infected. The source of the external infection in the herd could not be identified.     

Enzootic simian piroplasm (Entopolypoides macaci ) in wild-caught Kenyan non-human primates

Background Three species of non‐human primates comprising African green monkeys (AGMs), (Cercopithecus aethiops, n = 89), Syke’s monkeys (Cercopithecus mitis, n = 60) and olive baboons (Papio cynocephalus anubis, n = 30), were screened for Entopolypoides macaci. Methods Observation of blood smears prepared from these animals revealed E. macaci infection rate of 42.7% in AGMs, 35% in Syke’s monkeys and 33.3% in baboons. Results Gender infection rate was 38.2% in females and 29% in males. Statistically, there was no significant difference in infection rates between the monkey species and sexes (P > 0.05). Subsequent indirect immuno fluorescent antibody test supported the morphological appearance of E. macaci observed by microscopy. Sera from infected animals reacted positively (1:625) with E. macaci antigen, but not to Babesia bigemina or B. bovis antigen at 1:125 titer. Conclusion This study has revealed high prevalence of E. macaci infection in all three widely distributed Kenyan non‐human primates. With the continued use of these animals as models for human parasitic diseases, the presence of this highly enzootic parasite should be noted.     

Candidal vaginitis in hormone-treated mice: Prevention by a chitin extract

In view of findings from previous studies that a chitin soluble extract (CSE) blocked adhesion of Candida albicans in vitro and in vivo and prevented thereby a short lived candidal infection in naive mice, we attempted in the present study to block by CSE the development of a persistent infection, induced in hormone-treated animals. Continuous oestrus phase was obtained in mice by repeated weekly subcutaneous injections with estradiol benzoate. Intravaginal inoculation of the hormone-treated mice with 10⁷–10¹⁰ C. albicans cells induced a persistent candidal infection. Fifty three mice were pretreated intravaginally prior to inoculation of C, albicans with 2.5, 5.0 or 10 mg/mouse of a CSE cream and followed up for development of infection in comparison to 30 untreated animals. Twenty four hrs post fungus inoculation the infection rate among the CSE treated mice was 11–23% VS 84% among the controls; the rate increased a week later to 97% among the controls VS 41–50% among the CSE treated. Administering the CSE to the mice prior — and post-yeast inoculation (37 mice), led to increased efficacy of the treatment. The data, indicating that CSE is an effective measure for preventing persistent candidal vaginitis, may open the way to consider a similar approach for prophylaxis of vaginitis in human susceptible populations.     

Skeletal evidence of probable treponemal infection in free-ranging African apes

The prevalence and patterning of inflammatory lesions of the skeleton were investigated in samples of chimpanzees (Pan troglodytes troglodytes) and gorillas (Gorilla gorilla gorilla) curated at the Powell-Cotton Museum, Birchington, UK. One hundred and two chimpanzees (42 adults and 60 subadults) and 126 gorillas (50 adults and 76 subadults) comprise the samples. Twenty per cent of chimpanzees and 14% of gorillas were affected with a disseminated inflammatory skeletal condition caused by infection. The lesions appear to have originated as localized patches of new bone deposition on the surface of long bones and to have progressed to infection of the bone cortex and marrow. Although female prevalence of involvement exceeds that of males in both species, the differences are not statistically significant. The age distribution of affected animals indicates that the disease began in some animals as early as 2 yr of age. Given the skeletal and demographic prevalence and patterning of the lesions as well as the ecology and behavior of these animals, the most likely diagnosis of the condition is a yaws-like treponemal infection.