ONE HEALTH – CONCEPT FOR TODAY AND TOMORROW

“One Health” has been defi ned as “the collaborative eff ort of multiple disciplines — working locally, nationally, and globally — to attain optimal health for people, animals and the environment”. One Health is a new initiative, but with the concept that extends back to ancient times. One Health is an interdisciplinary concept for complex health challenges from a holistic integrated perspective, more then a divided perspective based on different disciplines. Th ere is no isolation, wild animals, domestic animals, pathogens and diseases do not know of the political borders. The aim of the One Health initiative is to form unifi ed solutions applicable for the improvement of health of humans, animals and the environment. A workshop was organized for the representatives of all structures and levels of medical and veterinary services of Serbia. During four tasks, among joint working groups, the most important structure of One Health was proposed, introducing possible concept in Serbia.

SEROSURVEILLANCE OF EQUINE INFECTIOUS ANAEMIA IN A REGION OF VOJVODINA

Equine infectious anemia is a consequence of a persistant infection of the horses with Lentivirus. Pathogenesis of the disease is very variable, what can bee seen through a wide range of clinical forms of the disease – from inaparrent infection to death. Diagnostics of EIA is based on clinical symptoms, detection of antibodies and virus. Antibodies can be identified with Hi, VN, CFIT, cELISA, SA-ELISA and AGID test. RT-PCR technique enables the detection of and/or quantifi cation of viral RNA level in blood of infected animal. First reliable serological test for EIA was AGID test. Modified AGID test is considered today as aknowledged, international standard for the detection of antibodies against EIA virus and it enables detection of more then 95% of ll positive animals. Horses with positive fi ndings with this test are considered infected and should be euthanized or placed in strict isolation. Further measures to control the spread of this disease are insectvector control and disinfection of surgical and other equipment in use on successive animals. Th e results of a study during a twenty year period, in the region of AP Vojvodina show that from the total of 11.972 horses blood samples, with te use of AGID test, positive results were found in 21 or 0,17% of horses.

SEROEPIDEMIOLOGICAL INVESTIGATION OF MYCOPLASMA BOVIS IN CALVES

Within the multifactorial etiology of respiratory infections in cattle, Mycoplasmae play an important role. Most of the Mycoplasma microorganisms play a minor role in the development of the infections in cattle, contrary to Mycoplasma bovis (M. bovis) that is commonly the primary agent of the disease. Respiratory tract mucosa is the primary colonization site of M. bovis in cattle. Colonization of the upper respiratory tract of calves with M.bovis oft en occurs within the fi rst few weeks of life. Animals with chronic infection and without clinical symptoms occasionally shed M.bovis and they are highly important for the epidemiology of the infection. Stress factors such as transportation, entrance into the feeding object, coldness, etc. are associated with the secretion of M. bovis from a nose. Diagnostic procedure relies on clinical symptoms and detection of causative agent, regardless of whether the infection is found in individual animals or in the entire herd. Serological detection of M.bovis antibodies is often a reliable diagnostic method. The most used indirect method is ELISA test. During a two-year period, blood serum samples from calves (beef cattle) were examined and analyzed. Calves originated from cattle farms (big and small) of Holstein- Friesian and Simmental breed. The total number of 3777 samples was examined applying ELISA (Biovet Inc. Mycoplasma bovis Antibody Test Kit Bovichek® M.bovis). Positive fi ndings were obtained in 182 animals, i.e. 4.81%. Th e obtained results confi rmed the presence of M.bovis in cattle herds. Further research from epizootical aspect and the role of M.bovis in the occurrence of health problems in cattle population is necessary.

Emerging Vector-Borne Diseases - Incidence through Vectors

Vector-borne diseases use to be a major public health concern only in tropical and subtropical areas, but today they are an emerging threat for the continental and developed countries also. Nowadays, in intercontinental countries, there is a struggle with emerging diseases, which have found their way to appear through vectors. Vector-borne zoonotic diseases occur when vectors, animal hosts, climate conditions, pathogens, and susceptible human population exist at the same time, at the same place. Global climate change is predicted to lead to an increase in vector-borne infectious diseases and disease outbreaks. It could affect the range and population of pathogens, host and vectors, transmission season, etc. Reliable surveillance for diseases that are most likely to emerge is required. Canine vector-borne diseases represent a complex group of diseases including anaplasmosis, babesiosis, bartonellosis, borreliosis, dirofilariosis, ehrlichiosis, and leishmaniosis. Some of these diseases cause serious clinical symptoms in dogs and some of them have a zoonotic potential with an effect to public health. It is expected from veterinarians in coordination with medical doctors to play a fundamental role at primarily prevention and then treatment of vector-borne diseases in dogs. The One Health concept has to be integrated into the struggle against emerging diseases. During a 4-year period, from 2009 to 2013, a total number of 551 dog samples were analyzed for vector-borne diseases (borreliosis, babesiosis, ehrlichiosis, anaplasmosis, dirofilariosis, and leishmaniasis) in routine laboratory work. The analysis was done by serological tests – ELISA for borreliosis, dirofilariosis, and leishmaniasis, modified Knott test for dirofilariosis, and blood smear for babesiosis, ehrlichiosis, and anaplasmosis. This number of samples represented 75% of total number of samples that were sent for analysis for different diseases in dogs. Annually, on average more then half of the samples brought to the laboratory to analysis for different infectious diseases are analyzed for vector-borne diseases. In the region of Vojvodina (northern part of Serbia), the following vector-borne infectious diseases have been found in dogs so far borreliosis, babesiosis, dirofilariosis, leishmaniasis, and anaplasmosis.

COMPARATIVE INVESTIGATION OF DIFFERENT METHODS FOR THE DETECTION OF INFECTION IN RABBITS CHALLENGED WITH L. interrogans SEROTYPE hardjo

Keeping up-to-date with modern diagnostic techniques for leptospirosis as well as continuous improvement of laboratory diagnostic methods resulted in abundant knowledge on the nature and consequences of this infection and its importance in both human and veterinary medicine. In that respect, development and introduction of novel diagnostic tests and procedures have become the paramount issue in the diagnostics of leptospirosis and related infectious diseases. Thus, the goal of this research was to investigate the application of diverse laboratory methods and to evaluate their validity in the diagnostics of leptospirosis. Eleven rabbits were artificially infected with live cultures of L. interrogans serovar hardjo by the method of skin scarification. Blood and blood serum samples of challenged animals were collected every other day throughout the 3-week period (i.e. until day 21), and then once weekly during following five weeks. Blood sera were tested for the presence of L. interrogans serovar hardjo specific antibodies applying the methods of microscopic agglutination (MA) test and ELISA. Blood samples were examined using the method of cultivation in liquid medium by Johnson supplemented with 200μg/1ml 5- fluorouracil (5-FU). Presence/absence of L.interrogans serovar hardjo was confirmed by polymerase chain reaction (PCR) method. In this reaction, a pair of primers separated from the basic structure of the Leptospira interrogans rrs (16S) gene. In MA test, the presence of specific antibodies against L. hardjo in rabbits was confirmed in 67 (36.61%) of 183 investigated sera. Initial positive specific antibody finding was recorded on day 9 post challenge, and it persisted until day 17. In ELISA test, positive and suspect findings were confirmed in 67 and 18 samples, respectively. Initial ELISA-positive finding was observed on day 15, showing increasing tendency throughout the monitoring period and reaching its maximum value on day 42. Method of blood sample cultivation resulted in isolation of L. interrogans serovar hardjo in 33 (18.03%) on day 3 at the earliest, whilst highest isolation rate was observed on day 17 post challenge. Applying polymerase chain reaction (PCR) method, genome or genome sequences of L. interrogans serovar hardjo were detected in 67 (56.30%) out of 119 blood serum samples. PCR method revealed positive finding as early as on day 1 post challenge, whereas the highest rate of positive findings was recorded on day 19. Comparison of the results obtained by methods of cultivation and PCR during the period from experimental day 1 to 21, i.e. period prior to administration of chemotherapeutic agents, demonstrated high level of linear correlation of r = 0.8105 at the 0.01 significance level. After dihydrostreptomycin therapy administered from day 21 post infection, L. interrogans serovar hardjo could not be isolated using the method of blood sample cultivation. Contrary to that, PCR method revealed the presence of L. interrogans serovar hardjo genome in 23 samples.

Q FEVER EPIDEMIOLOGY AND CONTROL IN DOMESTIC ANIMALS

The significance of each domestic animal in the epidemiology of Q-fever is different in various regions and it depends on the number of animals, level of infection, herd size, type of breeding and the conditions of hygiene. Epizootiological studies in our country show greater prevalence in sheep, than in cattle. Q-fever is maintained in Vojvodina in endemo-epidemic form. In Q-fever management programs for control of in sheep and cattle, serological examination and vaccination of the animals is recommended. Efficiency of the application of these measures should be conducted by applying recommended serological tests and detection of causative agent should be done by PCR method. A study on the comparative examination of efficiency, of different vaccination protocols has not yet been conducted. This would refer primarily to the duration of vaccination program, animal categories that are supposed to be vaccinated and timing for vaccination. A significant decrease in the level of infection was found after vaccination during the first years upon application of vaccination program. When vaccination in heifers was done before pregnancy with vaccines containing C.burnetii phase I strains, it was five times less likely that the infection would occur. Vaccination of cows with chronic infection prevents shedding of riketsia via milk, regardless whether the shedding is constant or intermittent. Vaccination represents a new concept of suppression of this zoonozes in the terms of human protection, and also in the terms of creating areas free from Q-fever in endemic regions. General preventive measures applied in the case of Q-fever infection are: movement restriction, separation of animals, restriction of milk and wool, adequate hygiene, using the protective clothing, desinfection of equipement and vechicles, removing of placenta particles, removing of manure, quarantine after calving and lambing and not use common grazing. People proffesionally exposed to the risk from infection should be educated about the disease.

MYCOPLASMA AS THE CAUSE OF INFECTIONS IN CATTLE

During the last few years more than 20 different types of Mycoplasma, Ureaplasma and Acholeplasma microorganisms have been isolated from cattle with different clinical signs. Most of Mycoplasma microorganisms have a secondary role in the appearance of infection in cattle. Differently, Mycoplasma bovis (M. bovis) has a primary role in the infection of cattle. It has been proved that M. bovis frequently causes pneumonia, mastitis and arthritis in cows. Besides, M. bovis is identified as a causative agent in meningitis, middle ear infection, keratoconjunctivitis, decubitus abscesses, vaginitis and miscarriages in cows. Diagnostic was done based on the clinical signs and detection of the causative agent, in individual animals and in the herds as whole. The methods used for diagnostic can be cultivation of the causative agent or fluorescence test for antigen detection in pathological material. Also, the detection of specific antibodies can be done, applying different serological methods: fast agglutination on a plate, indirect hemiinhibition, agar gel immunodifussion, CF, ELISA, etc. Polymerasa chain reaction (PCR) is a sensitive method which is mostly used for confirmatory etiological diagnostic. The treatment of Mycoplasma infection is very demanding due to the resistance to most frequently used antibiotics and therefore very different from treating any other bacterial infection. M. bovis is one of the most complicated agents for control as its response to the treatment is weak. A good program for eradication of mycoplasmosis is based on early carrier detection and they are excluded the herds.

CANINE VECTOR-BORNE ZOONOSES IN VOJVODINA

Research on vectors and zoonozes in Serbia has been going on for more than a decade now. Due to the climate changes during the last years, the presence of vectors has changed and also the presence of zoonotic agents inside them has changed, too. Vectors that can be found are ticks, mosquitoes, flies, etc. Ticks that can be found in Vojvodina are Ixodes ricinus, Dermacentor marginatus, Rhipicephalus sanguineus, Rhipicephalus bursa, Haemaphysalis punctata. The most common diseases known as tick borne in Vojvodina are piroplasmosis, Q fever and Lyme disease. The study done recently has shown that the presence of ticks can be found throughout the whole year in Northern part of Serbia (Vojvodina province). During the last five years different surveys have shown that ticks in Serbia are infected with B. burgdorferi s.l. at a rate of 25-30%, depending on the region. Also, a number of clinical cases of Lyme disease has been registered in humans and dogs. The percentage of ticks infected with B. burgdorferi s.l. in the province of Vojvodina ranges from 25-28%. An analysis of ticks in selected urban regions performed during a three-year period revealed an infection rate of 25%. During the three-year study period, a total of 1224 ticks were collected from different locations in Vojvodina. The dominant species was Ixodes ricinus, accounting for 62% of all collected ticks. Mosquitoes are another vectors that can be found in Vojvodina very often during the warm period of the year (June-October). Diseases that they can carried are blue tongue disease, equine infectious anemia, dirofilariosis in humans and dogs, etc. Diagnostic of dirofilariosis in Serbia begun some 4 years ago when Dirofilaria were found (Dirofilaria immitis and Dirofilaria repens) in dogs and later on in humans. First cases of dirofilariosis were found in dogs during the autopsy as a side finding. The presence of Phlebotominae has been detected in southern Serbia long time ago and they are known as vectors for leishmaniosis. Their presence has still not been detected in Vojvodina. Three years ago ago several dogs were found with clinical signs (epistaxys, cachexia, pale mucosa, skin leisures, blindness, lethargy) and seropositive finding for leishmaniosis in the central part of Serbia and Vojvodina. At first, all of the dogs were infected abroad, but since 2010, few dogs have been found that have never left their homes. During the period 2008-2010 in Scientific Veterinary Institute „Novi Sad“ 23 dogs vere examined for the presence of antibodies against leishmania by ELISA serological method.

Borrelia burgdorferi in ticks and dogs in the province of Vojvodina, Serbia

Lyme disease is a tick borne zoonotic infection, caused by Borrelia burgdorferi s.l. bacteria. For the transmission of the disease, the presence of ticks is a prerequisite. Lyme borreliosis mostly occurs in people and dogs, but it may occur in other animals. Ticks which carry B. burgdorferi s.l. in Serbia are of the Ixodes ricinus specis. In Serbia, Lyme disease was detected for the first time in the late '80-es. In dogs, clinical symptoms may occur even months after a tick bite, and include weakness, lymphadenopathy, fever, lameness, arthritis, etc. In our survey, we have observed tick and dog populations in the province of Vojvodina (northern part of Serbia). I. ricinus ticks were collected and examined for the presence of B. burgdorferi s.l. in several chosen locations. In addition, blood samples were collected from house dogs and pets from the same locations, and analyzed for the presence of antibodies specific for B. burgdorferi s.l. The results showed a mean infection of ticks of 22.12%, and a mean seroprevalence of Lyme disease in dogs of 25.81%. We conclude that in Vojvodina there is an actual risk of Lyme borreliosis for other animals and humans, because of the persistence of B. burgdorferi s.l. in both tick and dog populations.

CURRENT APPROACHES TO DIAGNOSIS OF PARATUBERCULOSIS IN CATTLE

Diagnostics of paratuberculosis aims at two goals: first, monitoring the herd, and second, reliable identification of positive animals. Bovine paratuberculosis is diagnosed by the application of direct methods, i.e. by identification of the agent, or indirectly by measuring immunology response. The relevance of a diagnostic method is determined by the stage of the disease in animal. Direct identification of Mycobacterium avium subsp. paratuberculosis in a feces sample is limited by the fact of small number of secreted bacteria by intermitent secretion. Bacteriological examination of feces is a valuable diagnostic procedure for detection of animals with clinical symptoms and the animals with subclinical manifestation. Direct identification of MAP in feces and organ samples using PCR method considerably shortens the time for proving the evidence of a disease. The indirect methods for proving the prevalence are complicated and limited. ELISA assay is considered the method of choice for diagnosis of paratuberculosis due to its rapidity and relatively low costs. Despite continual and numerous research, the problem of detecting subclinical infection has not been solved yet especially in the herds with low prevalence of positive animals. Numerous efforts of researches have been done in order to improve the current methods and develop new diagnostic procedures for diagnosis of paratuberculosis. However, already now the control of the disease is possible due to the combination of regular diagnostic through sanitary measures and identification of the infected animals.

STRUCTURE AND DISTRIBUTION OF LEADING ZOONOSES IN VOJVODINA IN 2000-2009 PERIOD

The data show that from more than 1.400 today known microorganisms, that cause infections in human population, 61% is of animal origin. The list of known zoonoses is enlarged every day, new diseases are recognized and discovered. Because of this, zoonoses are significant health and economical problem in the world. The participation of these diseases in national pathology of the inhabitants of certain area depends on the presence and number of foci, type of reservoir species, application and efficency of prophylactic measures. The goal of this paper is to analyze the structure and distribution of leading zoonoses in the population of AP Vojvodina. The analysis is made according to the data from the register of infectious diseases - Center for Disease Control and Prevention, Institute for Public Health of Vojvodina. The period included in this study is from 2000 to 2009. From 70 infectious diseases, which are to be declared according to national legislative, half of them are zoonotic diseases. In this analysis we treat only zoonotic diseases and vector borne zoonotic diseases registered in past 10 years. In the period included in this study 15 zoonotic diseases and vector borne zoonoses have been registered in AP Vojvodina. The highest level of incidence is for lyme disease, with the average 9,91/100.000 and trichinellosis with the average 6.40/t 100.000 (Table 1). Toxoplasmosis, Q fever, leptospirosis and echinococcosis have been registered in Vojvodina regularly, and the average incidence is below 1/100.000. The range from minimal to maximal registered incidence shows that there was not a significant difference in epidemiological situation of these diseases. Other zoonoses have been registered rarely and occasionally, as autochthonous or imported diseases (leishmaniasis). In this group of diseases 41 deaths have been registered. Most of it was caused by tetanus and leptospirosis. The lethality rate of tetanus was 54.55% and the patients were of the oldest age. Lethality rate from leptospirosis was 12.0%, and unlike tetanus, the patients belonged in the middle age group. The registered incidences of zoonoses in human population do not present the real situation because of the diagnostic and rapid recognition of symptoms. Some vector borne zoonotic diseases, like for example tick born meningoencephalitis and West Nile Virus fever, which regularly occur in Europe and surrounding countries, have not yet been registered in our region and Serbia. However, the risk from the infections and a possibility of occurrence is not eliminated.

POTENCY TESTING OF ATTENUATED LIVE VACCINE LAVIR- K® AGAINST CLASSICAL SWINE FEVER

In the paper are presented the results of investigating protective effect of attenuated live vaccine against classical swine fever (CSF) under experimental conditions. The vaccine contains C-strain of CSF. In the Republic of Serbia it is used for systemic immunoprophylaxis. Potency testing was performed according to the guidelines of the European Pharmacopoeia, 5th Edition, 2005 (01/2005:0065) and the guidelines published by the World Organisation for Animal Health (OIE) (Manual of Diagnostic Tests and Vaccines for Terrestrial Animals, 5th Edition, 2008, Vol. 1, Chapter 2.8.3). The experiments were carried out on twelve weaner pigs seven weeks of age randomly assigned to two groups consisting of five, and one group consisting of two pigs. Before introducing the experimental protocol of vaccination and artificial infection, the presence of specific antibodies against CSF was controlled by ELISA test, i.e. by serum neutralisation test that proved no presence of antibodies against bovine virus diarrhea (BVD). The pigs in the fist group were vaccinated with attenuated live vaccine Lavir-K® (Veterinary Institute Zemun a.d. Belgrade) in a 1:40 dilution, and the pigs from second group were vaccinated in a 1:160 dilution. The group three served as a control group that was not vaccinated. Fourteen days post vaccination all animals were challenged with highly virulent CSF virus strain Beker, and fourteen days after artificial infection animals were daily observed and their body temperature was recorded. In the group of animals vaccinated with vaccine Lavir-K® in a 1:40 dilution there were no clinical characteristic symptoms of CSF, while in the group vaccinated in a 1:160 dilution two pigs became ill with obvious CSF symptoms. One pig died on day 7 p.v. In the control group, i.e. two non-vaccinated pigs, there was an acute form of CSF and they died seven days after the infection. Calculation of the Protective Dose 50 (PD50) of Lavir-K® was done using the equation by Spearman-Kaerber and it was calculated to be 184. Having in mind that one vaccine doses should have protective value of > 100, it may be concluded that tested vaccine fulfils the requirements for vaccine potency as laid down in the European Pharmacopoeia and the OIE Manual of Diagnostic Tests and Vaccines for Terrestrial Animals.

LABORATORY DIAGNOSTICS OF CURRENT INFECTIOUS DISEASES ACCORDING TO INTERNATIONAL STANDARDS

One of the greatest challenges of modern laboratory diagnostic is selection of methods and procedures for fast and reliable diagnostic. Contemporary laboratory diagnostic is faced with the request to develop the technologies for rapid detection of agents and identification of biological features, as for example pathogenicity, group affiliation, sensitivity, or even genetic sequencing. Beside the aforementioned requests, laboratory diagnostic must implement numerous international standards and apply the principles of good laboratory practice. By compliance to international standards, i.e. good laboratory practice, laboratory diagnostic has considerably been improved, especially regarding the validity of the obtained results. With the aim to improve laboratory diagnostic of infectious diseases in veterinary medicine, this paper presents the demands of the standard SRPS ISO/IEC 17025:2006 (General Requirements for the Competence of Testing and Calibration Laboratories), SRPS ISO 15189:2008 (Medical Laboratories – Particular Requirements for Quality and Competence) as well as the demands of World Organization for Animal Health (O.I.E). Implementation of these standards is presented through the procedures of laboratory diagnostic of most important bacterial and viral animal infections on the territory of the Republic of Serbia. This paper presents the demands regarding the reference material, equipment, workspace and staff, for the laboratory diagnostic of the following diseases: anthrax, leptospirosis, paratuberculosis, Q fever, chlamydiosis, tuberculosis, mycoplasmosis, brucellosis, listeriosis, pasteureliosis, salmonellosis, clostridiosis, Aujeszky’s disease, blue tongue, rabies, infectious bronchitis in poultry, influenza, atypical poultry plague, infectious bursitis, Mareck’s disease, bovine viral diarrhea, enzootic bovine leukosis, infectious bovine rhinotracheitis, equine infectious anemia, equine rhinopneumonitis, equine viral arteritis, maedi-visna, classical swine fever and porcine reproductive and respiratory syndrome.

EXAMINATION OF BRUCELLA OVIS (OVINE EPIDIDIMYTIS) INFECTION IN SHEEP

Brucella ovis is caused by clinically manifested disease named ram epididimytis. The causative agent is a gram-negative coccobacillus or short rod, facultative intracellular pathogen. The diseases is characterized by genital lesions manifested in a form of epididimytis and plecentitis in sheep, but the in fection may also be subclinical. The consequences of this disease are reduced fertility in rams, frequent abortions in sheep and in creased perinatal mortality. Most of ten the infection enters into a flock through in fected rams, that shed great num ber of Brucella, however passive genital transmission is the usual way of infec tion. B. ovis causes inflammation of epididymis, semen and influences the fertility of rams, but in sheep it causes abortion and placentitis. Rams are more susceptible than sheep, and the disease affects adult animals. The diagnosis based only on clinical identification most of ten is not sufficiently reliable, so the samples of semen, vaginal swab, milk and the smears of susceptible tissues are taken and then stained, microscop i cally examined and cultivated on nutritive agar. Our examination encompassed sheep and rams from the munic ipalities in South ern Bačka and Srem district, as well as the samples from Middle Banat. The examination included also the rams with clinicalsymptoms of epididimytis, what had bee proven by NIV-NS. There were 1500 sera samples from sheep and rams examined by the method of complement fixation (MCF). The findings of specific antibodies against B. ovis in dilution 1:5 was considered positive. Specific antibodies against B.ovis were de tected in the sheep that originated from Bečej and Titel municipality, Southern Bačka district. The prevalence was very low and was 0.89%. In Middle Banat district, where only rams were examined, a higher prevalence was diagnosed for B. ovis (4.29%), but in Srem district no animals were seropositive on B. ovis. The examined rams with clinical symptoms of epididimytis were not seropositive on B.ovis.

BIOFILM – ORGANISATION OF BACTERIA LIFE IN NATURAL ECO SYSTEMS

In all natural ecosystems, including both humans and animals, bacteria show a tendency to bind on the surface and form a structure known as biofilm. Biofilm formation is a genetically regulated process in the life of bacteria and has several phases demanding intercellular communication. In biofilms bacteria express different characteristics comparing to their free suspended counterparts, due to different gene transcription profile and increased resistance towards antibiotics and disinfectants. Discovery of microbial biofilms has changed our understanding of bacteria, that are not viewed only as unicellular organisms, but more as a multi-cellular community that in some characteristics imitates primitive eukaryotic tissue. In the last decades there is an increasing evidence on infections caused by bacteria that form biofilms, and have a chronic course with possibility of recidives. Conventional methods of killing microbes by antibiotics and biocides is usually ineffective in bacteria organized in biofilms.

PREVALENCE OF MAEDI-VISNA IN SHEEP HERDS

Progressive sheep pheumonia and maedi are terms that denote chronic virus sheep disease. Maedi-visna virus causes a disease named visna, which is a disease of nervous system with the symptoms of paresis and paralyses. Besides pneumonia, maedi-visna is characterized by arthritis, heavy mastitis and slow growth of lambs. This diseases is closely related to encephalitis and goat arthritis. Virus maedi-visna and the virus of sheep progressive pneumonia are neoncogen sheep retroviruses that belong to a subfamily Lentvirinae. They cause persistent infection with lymphoproliferatic changes, mammary gland tissues, brain and joints. The earliest reports on the disease come from South Africa and SAD, but nowadays the disease is present in all the countries where sheep are raised. The ways of transmission and their importance are still not detected. Incubation period is very long, and most of sheep with clinical symptoms are older than 3 years. The most common symptoms are apathy, weight loss and exhaustion. It may be followed by coughing and nasal discharge, pneumonia as a consequence of secondary bacterial infection. The changes on mammary gland appear slowly, the udders are enlarged and hard, but papillae are flaccid. Due to changes on mammary glands lambs of the infected sheep are often weak and less developed. Clinically, the disease lasts 3-10 months always with fatal outcome. The virus may be isolated on tissue culture or identified with the method of complement fixation and virus neutralisation test. Different serology methods are used for diagnostics: agar gel immunodiffusion test, indirect immunofluorescence test and ELISA test. This survey included 2000 sera samples from sheep in 4 epizootiology areas of the Scientific Veterinary Institute of Serbia (NIVS) Belgrade, Veterinary Specialist Institute (VSI) Sombor, Veterinary Specialist Institute (VSI) Subotica and Veterinary Specialist Institute (VSI) Zrenjanin, each with 500 representative samples. The detection of specific antibodies against maedi-visna virus (MVV) was done by ELISA technique, using commercial set kit CHEKIT-CAEV/MVV, produced by IDEXX. Based on the obtained results from 2000 seep sera tested forMVVantibodies, in 325 cases (16.24%) sheep were seropositive, while only 45 (2.25%) sheep were suspicious (ambiguous). The disease is important because of economic losses, what restricts trade. The fact that MVVis proved in sheep population points out the fact that more attention should be given to this infection.

Scanning tunneling microscopic (STM) analysis of the phospholipid bilayer surface characteristics in the P beta phase. Secondary ripples

Previous investigations have elaborated on the necessity for dimyristoylphosphatidylcholine (DMPC) molecules to conform in a ripple phase at the temperature intermediate between the transition and pretransition in order to protect the hydrophilic-hydrophobic polarity of the bilayer. Present observations, in addition to the asymmetric P beta phase of 11.1 +/- 1.3 nm wave-length, demonstrate orthogonal corrugations perpendicular to the main wave direction. Whether this is a prerequisite for maintaining the molecular order-disorder balance at such specific temperature, or it results from yet unknown source is unclear at present.

Effect of maternal exposure to smoke on gas diffusion capacity in neonatal rat

Offspring of control and experimental (chronically exposed to whole cigarette smoke) rats were sacrificed on 15th postnatal day. Pulmonary tissues were processed for quantitative electron microscopic analyses. Arithmetic and harmonic mean thicknesses were directly measured and diffusion capacity was derived for separate layers (tissue, plasma, erythrocyte) and the entire lung. Experimental offspring showed a greater volume density of interstitium in parenchyma (P less than 0.04), arithmetic (P less than 0.05) and harmonic (P less than 0.009) mean thicknesses. Diffusion capacities for lungs of both animal groups, however, were similar (0.00543 and 0.0054 cm3 O2.min-1.mm Hg-1.g body weight-1 for control and experimental lungs respectively). Experimental tissue appeared better adapted for optimal exchange of gases (P less than 0.05), as indicated by corrugation index (ratio between arithmetic and harmonic mean thicknesses) than for the control counterpart. In spite of induced alterations in several developmental processes by a presently used experimental procedure, tissue capacity for transport of gases was not significantly changed in either the alveolo-capillary membrane or the entire lung.

Differentiation of interstitial cells and stromal proteins in the secondary septum of early postnatal rat: effect of maternal chronic exposure to whole cigarette smoke

The intention of this investigation was to ascertain the effect of maternal exposure to cigarette smoke on the early postnatal morphogenesis of pulmonary interstitium in offspring. Female rats were chronically exposed to whole cigarette smoke. Offspring of these and control animals were sacrificed at postnatal day 15, and their tissues were prepared for quantitative and qualitative analyses. Results indicate a diminished quantitative representation of parenchymal tissue (P less than 0.01) and a slower pace of secondary septal growth (P less than 0.07) in the experimental lung. Furthermore, a greater cellular volume density (P less than 0.0002) and, inversely, a lesser quantitative representation of extracellular matrix (P less than 0.0002) was ascertained for the experimental septal interstitium. There was proportionately less of elastin substances (P less than 0.009), collagen together with basal laminae (P less than 0.0008), and nonfibrillar, amorphous matrix (P less than 0.02) in the experimental extracellular stroma. Fibrillar collagen and nonfibrillar matrix were represented quantitatively 6.3 times more in the experimental extracellular interstitium than elastin, whereas that ratio for the control tissue was only 4.2. Most experimental interstitial cells (80%) contained numerous lipid globules, which, in contrast, were only occasionally present in control cells (7.3%). Experimental cells, consequently, possessed a larger cross-sectional diameter and a smaller nucleus-to-cytoplasm volume ratio than control cells. These divergent developmental patterns are possibly suggestive of a delayed differentiation of interstitial cells and a modified production to degradation balance of stromal proteins in offspring of animals chronically exposed to whole cigarette smoke.

The embryogenesis and anatomy of Waldeyer's ring

The developmental history of the embryonic germ disk is briefly traced through the bilaminar, trilaminar, and bodyfold stages with emphasis on the pharyngeal arches, pouches, and clefts. This is followed by a discussion of the genesis and adult anatomy of the tonsillar tissues.

Morphometric analysis of the remodeling of the rat pulmonary epithelium during early postnatal development

In the rat lung the alveoli are formed in the early postnatal period. Within 3 weeks the alveolar surface area increases more than five-fold and the saccular lung reaches its mature structure. In order to analyse the changes in the compartments of the parenchymal tissue, the lungs of three animals per group aged 4, 13, and 21 days, respectively, were investigated by means of electron microscopic morphometry. Whereas the capillarisation of the interalveolar septa almost doubled in the period investigated, the endothelium and alveolar epithelium increased their share of the septal tissue at the expense of the interstitial compartment. The cellularity of the interstitium decreased markedly with age, the ratio of cells to interstitial spaces falling from 5.1 to 1.7. Within the epithelium, the type II cell population increased its mass almost six times, representing 58% of the alveolar epithelial volume at 3 weeks. Accordingly, the portion of alveolar surface area covered by type II cells was highest on day 21, with 9% versus 5.6% on day 4, and around 3% in a normal adult lung. The observed quantitative structural changes are discussed in the light of the functional demands of the organ: the need for an expanding alveolar surface area to be covered by a thin epithelial lining layer, the maintenance of a thin air-blood barrier, and a quantitatively adapted secretion of alveolar surfactant.

Estrogen and tracheal secretion: the effect of estrogen on the epithelial secretory cells of the rat trachea

Epithelial secretory cells of the tracheal mucosa obtained from ovariectomized control and ovariectomized estrogen-treated rats were studied morphologically by scanning and transmission electron microscopy and by the combined periodic acid Schiff (PAS) and alcian blue (AB) staining method. A significant decrease was observed in the number of large PAS-reactive secretory cells following estrogen treatment. Concomitantly the number of the Mixed+ cells containing both weakly acid and neutral glycoproteins was found to increase significantly. A majority of the observed secretory cells exhibited either an apical protrusion loaded with secretory granules, extending to a maximum distance of 7.9 micrometer into the tracheal lumen or an apical indentation devoid of mature secretory granules, descending to 5.6 micrometer below the luminal surface. The frequency of cells exhibiting an apical indentation was significantly greater in estrogen-treated animals than in controls. The present findings indicate that estrogen treatment of ovariectomized rats results in: 1) an increase in the synthesis of weakly acid glycoprotein within tracheal secretory cells; 2) a concomitant decrease in the frequency of secretory cells containing neutral glycoprotein; and 3) a general increase in the secretion by the tracheal cells.

Clinical correlation of anomalies of the supraglottic larynx with the staged sequence of normal human laryngeal development

The clinical correlation of the authors' observations on human laryngeal development with existing literature supports the suggestion that earlier concepts, specifically by Frazer, may not be valid. It is further proposed that development of the human larynx may similarly correspond in man to that of the rat. Congenital laryngeal malformations are fundamentally associated with a disturbance of epithelial mesenchymal interactions, particularly related to a premature arrest of the normally vigorous epithelial activity.

Ultrastructure of the secretory cells of the submucosal glands in the human maxillary sinus

Tissue samples obtained from the lateral wall of the maxillary sinuses of five patients were examined by light microscopical, histochemical, and ultrastructural techniques. Submucosal glands were tubulo-alveolar mixed glands. The acini consisted of either all serous or all mucous cells, or a mixture of both. Serous granules were stained by toluidine blue, or by hematoxylin and eosin (H and E), but showed little or no reaction with periodic acid-Schiff (PAS) or Alcian blue. Mucous granules were pale in toluidine blue or H and E preparations, and consisted primarly of acid mucosubstances, as demonstrated by their staining reaction with PAS and Alcian blue. At the electron microscope level, the serous granules were either homogeneously dense, or showed a substructure consisting of at least two layers of distincly different electron-opacity. Typical mucous droplets consisted of a fibrillar network dispersed in a translucent matrix. A second secretory product was present in the mucous cells in the form of elongated, membrane-bounded structures containing numerous parallel filaments, which measured about 55 A in diameter. The mucous droplets and the filamentous bodies appear to arise from the opposite faces of the Golgi complex in the mucous cells. The filamentous bodies showed a pronounced tendency to fuse with the mucous droplets. All acini were surrounded by a well-defined myoepithelial layer and contained intercellular nerve terminals.

Variations in height of the palatum osseum as a function of other vertical dimensions and angles of the skull

Study of 500 Yugoslav skulls revealed average values of the height of the palatum osseum. In comparisons, no differences in average values were found in age and sex groups studied.