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Diabetes mellitus is a metabolic disease that results in long-term hyperglycemia. Among the many long-term complications associated with diabetes, manifestations in the hand include Dupuytren's contracture, trigger finger, compressive neuropathies, and infections. These conditions can have a profound impact on a patient's quality of life, highlighting the importance of timely recognition and treatment of these manifestations. This review aims to provide updated information regarding the incidence and outcomes of these clinical manifestations in the diabetic versus nondiabetic population. A systematic review based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist was performed. The literature search included the use of PubMed and Ovid databases to find relevant articles that were then selected based on an inclusion criterion that required level 4 evidence. Diabetes mellitus results in an increased incidence of Dupuytren's contracture, trigger finger, carpal tunnel syndrome, cubital tunnel syndrome, and hand infections. Dupuytren's, trigger finger, and carpal tunnel syndrome all had similar outcomes, while diabetic patients had worse outcomes related to infections. There was a lack of data regarding the effect of diabetes on cubital tunnel syndrome. Future studies should be performed to analyze the effects of diabetes mellitus on hand manifestations, particularly regarding the outcomes of diabetic patients with cubital tunnel syndrome., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

With the development of defined media for general and specific use with cell cultures, and concern over the use of human cells and over potential prion infections associated with growth factor extracts such as bovine pituitary extract, an animal product-free medium has become available. The basic keratinocyte defined medium can be used with a choice of animal product-containing or animal product-free supplements. Human corneal epithelia cell lines were cultured in the media with these two types of supplement, and compared in terms of their growth rates, their capacity to form tight barriers, and calcium regulation of the location of a junction-associated protein, zonula occludins-1 (ZO-1). The growth rates were not different in the two media, as long as the recommended coating was applied to the culture flask for the animal product-free medium. The barrier function was equally effective for confluent cultures seeded at the same densities. A calcium concentration of 100 microM or above resulted in ZO-1 localisation at the cell membrane in either medium. Hence, cultures in the media are comparable, when the coating is employed. Further experiments are being conducted to establish the comparability of responses to chronic treatment with surfactants.

Ten African swine fever virus isolates from the soft tick Ornithodoros erraticus collected on three farms in the province of Alentejo in Portugal were characterized by their ability to cause haemadsorption (HAD) of red blood cells to infected pig macrophages, using restriction enzyme site mapping of the virus genomes and by experimental infection of pigs. Six virus isolates induced haemadsorption and four were non-haemadsorbing (non-HAD) in pig macrophage cell cultures. The restriction enzyme site maps of two non-HAD viruses, when compared with a virulent HAD isolate, showed a deletion of 9.6 kbp in the fragment adjacent to the left terminal fragment and of 1.6 kbp in the right terminal fragment and an insertion of 0.2 kbp in the central region. The six HAD viruses isolated were pathogenic and produced typical acute African swine fever in pigs and the four non-HAD isolates were non-pathogenic. Pigs that were infected with non-HAD viruses were fully resistant or had a delay of up to 14 days in the onset of disease, after challenge with pathogenic Portuguese viruses. Non-HAD viruses could be transmitted by contact but with a lower efficiency (42-50 %) compared with HAD viruses (100 %). The clinical differences found between the virus isolates from the ticks could have implications for the long-term persistence of virus in the field because of the cross-protection produced by the non-pathogenic isolates. This may also explain the presence of seropositive pigs in herds in Alentejo where no clinical disease had been reported.

A closed-tube polymerase chain reaction (PCR) was developed to allow the rapid detection of African swine fever virus (ASFV) DNA. This assay targets the VP72 gene of ASFV and uses the 5'-nuclease assay (TaqMan) system to detect PCR amplicons, avoiding tube opening and potential cross-contamination of post-PCR products. An artificial mimic was engineered with the TaqMan probe site replaced by a larger irrelevant DNA fragment allowing discrimination from ASFV by using two-colour TaqMan probe reporters. When added to the samples, successful amplification of this mimic demonstrated the absence of substances inhibitory to PCR, thereby validating negative results. Assay sensitivity was confirmed by obtaining positive signals with a representative selection of ASFV isolates. Many of the clinical and post-mortem features of ASF resemble those of classical swine fever (CSF) and porcine dermatitis and nephropathy syndrome (PDNS). Therefore, fast and reliable detection of ASFV is essential not only for the implementation of control measures to prevent the spread of ASF, but also in the differential diagnosis from CSF and PDNS. This assay should prove to be a valuable tool in the laboratory diagnosis of ASF and will complement existing molecular methods to provide rapid differential diagnosis in cases of suspected swine fever., (Copyright 2002 Published by Elsevier Science B.V.)

The aim of this study was to determine filial infection prevalence of experimentally infected colony Ornithodoros moubata Walton (Ixodoidea: Argasidae) ticks for African swine fever virus (ASFV). Three groups of ticks were used: an uninfected control group, one group orally infected with the VIC T90/1 isolate and another group orally infected with the LIV 13/33 isolate of ASFV. The results show that filial infection prevalences were not constant but were highly variable between egg batches from different ticks and between successive egg batches from the same tick. Filial infection prevalences ranged from 1.8% to 31.8% for ticks infected with the VICT90/1 isolate and from 1.2% to 35.5% for ticks infected with the LIV 13/33 isolate. A similar pattern was noted after the third feed. Immunohistochemisty showed that virus replicates in the developing larval cells and not in the yolk sac cells or within the outer layers of the eggs. The results show that ASFV can replicate to a high titre (10(5.1)log10HAD50) within the larval cells of the developing egg.

The effects of infection with African swine fever virus (ASFV) on adult and nymphal Ornithodoros moubata Murray (Ixodoidea, Argasidae) ticks were examined. Three groups of ticks were used, an uninfected control group, one group infected with the VIC T90/1 isolate of ASFV and another group infected with the LIV 13/33 isolate of ASFV. Infection with ASFV did not affect the oviposition rates of infected ticks when compared with uninfected ticks. There was no difference between infected and uninfected ticks in progeny hatching rates and first nymphal stage feeding rates. Feeding rates of infected adult ticks were also unaffected. However, a significant increase in mortality rates was observed amongst the adult ticks that fed on an infective bloodmeal compared to ticks fed on an unifected bloodmeal.

This paper describes a pilot scale treatment plant that has been designed and built for the thermal inactivation in pig slurry of two viruses that infect pigs--African swine fever virus (ASFV) and swine vesicular disease virus (SVDV). The plant treats pig slurry continuously at a rate of up to 100 litres/hour and functions by heating the slurry, maintaining at least 99.99% of the slurry at the required temperature for a minimum period of 5 minutes, and then recovering the heat to raise the temperature of the incoming slurry. Results obtained indicated that SVDV was inactivated in pig slurry to below detectable levels with an alkaline pH (pH 7.5 to 8, as is usually the case) at a temperature of between 50 and 55 degrees C. In acidified slurry (pH 6.4), inactivation occurred between 55 and 60 degrees C. The difference in inactivation temperatures was probably due to the presence of free ammonia in the unacidified slurry. ASFV was inactivated by operating the plant at a temperature of 53 degrees C at a pH of 8.

Assaying samples for infectious virus is more difficult when the sample is toxic to cells used in the assay, e.g. with samples of infected pig slurry. Various techniques were compared for the recovery of African swine fever virus (ASFV) and swine vesicular disease virus (SVDV) in pig slurry. Extraction with Freon led to 80-100% recovery of SVDV added to pig slurry. The assay sensitivity enabled undiluted, centrifuged sample to be put directly onto monolayers of IB-RS2 cells, allowing a minimum detection level of 100.7 pfu ml-1. ASFV was difficult to recover intact, and the best technique allowed a recovery of 60% with a minimum detectable level of 101.8 HAD50 ml-1, due to toxicity to the cells at low sample dilutions. Extraction with the addition of an equal volume of ox serum to inoculated slurry was best at recovering ASFV. Poor recoveries with the other techniques may have been due to the inactivation of the virus while in the slurry rather than as a result of the inability of the method to extract ASFV.

Warthog (Phacochoerus aethiopicus), giant forest hog (Hylochoerus meinertzhageni) and bushpig (Potamochoerus porcus) are known to be susceptible to infection with African swine fever (ASF) virus. Little however, is known about the ecology of the disease in the bushpig. This study has shown that the bushpig remains viraemic for between 35 and 91 days following infection during which time it is able to infect the tick vector O. moubata. These ticks were able to transmit the disease to pigs. The virus persists in the lymphatic tissues for less than 34 weeks. Bushpigs infected with LIL 20/l virus but not VIC T90/l virus transmitted infection to in-contact pigs. Infected domestic pigs did not transmit the infection to in-contact bushpigs. ASF virus was able to replicate in in vitro cultures of bushpig leucocytes and endothelial cells. Recovered bushpigs could be reinfected with some strains of virus but not others. While it has been demonstrated that bushpigs remain carriers of ASFV following infection a complete understanding of their significance in the epidemiology of the disease awaits further investigations of their association with O. moubata.

A viral haemorrhagic syndrome was induced in 14 pigs by inoculation with an African swine fever (ASF) virus strain of moderate virulence, to determine changes in megakaryocyte (MK) numbers and morphology and thus to assess the role of these cells in the thrombocytopenia characteristic of subacute ASF. The strain tested induced changes in the proportion of different types of MK (typical nucleated MKs, apoptotic MKs and immature MKs); it also caused subcellular lesions over the first 7 days post-inoculation (dpi). At 7 dpi, severe thrombocytopenia was observed. There was a statistically significant increase in apoptotic MK numbers. The MKs showed three stages in the course of the disease: a compensatory stage, represented by cytoplasmic projections, a hypermaturity stage, represented by apoptotic MKs, and a regenerative stage, represented by clusters of immature MKs. These changes, especially the presence of numerous apoptotic MKs, may explain the early and transitory thrombocytopenia detected in subacute ASF. The large number of apoptotic MKs observed may be associated with the accelerated maturation of these cells, resulting from the action of cytokines, or peripheral platelet consumption, or both.

Bone marrow samples from pigs infected with the highly virulent Malawi'83 or moderately virulent Dominican Republic (DR'78) isolates of African swine fever virus were studied by means of a double labelling immunohistochemical technique which stained the major structural protein VP73 of the virus and megakaryocytes simultaneously. In pigs infected with the highly virulent Malawi'83 isolate, 2.2 per cent of megakaryocytes were VP73+ five days after inoculation, and at six and seven days 2.5 and 9.5 per cent of megakaryocytes were VP73+. Some infected and uninfected megakaryocytes showed pyknosis and karyorrhexis, particularly at seven days after inoculation. However, in comparison with uninfected pigs, the number of megakaryocytes decreased only at seven days after inoculation. In pigs infected with the moderately virulent DR'78 isolate, only 0.2 per cent of megakaryocytes were VP73+ at eight days after inoculation. However, at eight, nine and 10 days after inoculation the total number of megakaryocytes was significantly lower (P < 0.01) than in control uninfected pigs, and the majority of the megakaryocytes showed signs of cell death such as pyknosis and karyorrhexis. The fact that this greater destruction of megakaryocytes was associated with the lower rate of infection of this cell type suggests that indirect damage to megakaryocytes is an additional mechanism of thrombocytopenia in acute and subacute African swine fever.

In order to determine the pathogenic mechanisms involved in lymph node haemorrhages in acute African swine fever (ASF), eight pigs were inoculated with ASF virus, strain Malawi'83. Lymph node haemorrhages were observed from three days post infection (dpi) onwards, coinciding with ASF virus replication in monocytes and macrophages adjacent to stimulated endothelial cells, phagocytic stimulation of capillary and small-vessel endothelial cells, increase in the number of fenestrations of endothelial cells, and endothelial cell loss, as well as clusters of blood cells and necrotic material beneath the endothelium. Vascular lumina were blocked by platelet plugs and fibrin microthrombi. These phenomena became more marked as the disease progressed. At five dpi, virus replication was also found in circulating neutrophils. At seven dpi, lesions were more intense and were accompanied by virus replication in sinus and capillary endothelial cells, and in other cell populations including pericytes, fibroblasts, smooth muscle fibres and reticular cells. The results obtained in this study suggest that lymph node haemorrhages are related to endothelial stimulation and the onset of disseminated intravascular coagulation. Virus replication in vessel wall cells occurs only in the final stages of the disease and plays a secondary role.

The effects of African swine fever (ASF) virus infection on bone marrow hematopoiesis and microenvironment were determined by studying the sequential development of ultrastructural lesions of bone marrow and blood cell changes. Eight pigs (two pigs/infected group) were inoculated by intramuscular route with 10(5) 50% hemadsorbing doses (HAD50) of the Malawi'83 ASF virus isolate. Two uninfected pigs were used as controls. Ultrastructural changes developed by day 3 postinoculation (PI), persisted through day 7 PI, and were characterized by activation of macrophages. From day 5 PI, viral replication was observed in monocytes/macrophages, reticular cells, immature neutrophils, and promonocytes. Also viral replication was detected in megakaryocytes, endothelial cells, and pericytes at day 7 PI. Vascular alterations consisted of activation of sinusoidal endothelial cells, intravascular coagulation, and fibrin strands interspersed among microenvironment and hematopoietic cells. No significant changes were observed in total white blood cells counts, percentage of monocytes, and platelet counts; however, severe lymphopenia and neutrophilia were detected from day 3 PI. Results of this experiment indicate that there is increased hematopoiesis in bone marrow during acute ASF, coinciding with macrophage activation. Neither vascular changes nor viral replication in different bone marrow cell populations gave rise to impaired bone marrow function. Increased hematopoiesis would exert a positive influence by preventing the early onset of thrombocytopenia and would exert a negative influence by stimulating the spread of the virus via neutrophils. Increased hematopoiesis would be unable to compensate for the lymphopenia.

Acute forms of African swine fever are characterized by hemorrhagic lesions in the lymphoid organs. This paper reports the evolution of lesions in the splenic cords of pigs inoculated with African swine fever (ASF) virus (strain Malawi'83). Ultrastructural examination of the splenic cords of the infected pigs revealed numerous macrophages attached to the muscle cells harboring virus replication center and cytopathic effects at 3 dpi (days post-infection). From 5 dpi, the splenic cords contained a large number of erythrocytes associated with abundant fibrin deposits, mainly arranged around the muscle cells, from which macrophages had disappeared. It is likely that the ASF virus replication, and consequent cytopathic effects, observed in the fixed macrophages of splenic cords, may be responsible for the fibrin deposition.

A study of the pathogenesis of acute African swine fever (ASF) was carried out in pigs inoculated with a highly virulent strain of ASF virus to determine the sequential development of the subcellular changes in a particular lymphoepithelial organ, the tonsil. The apoptosis of the lymphocytes and the inhibition of lymphocyte proliferation were the main changes that occurred in the tonsillar lymphoid structures. This may explain the early lymphopenia observed in acute ASF. Moreover, vascular changes, consisting of increased vascular permeability, activation of endothelial cells and loss of these cells, might have been the cause of the characteristic haemorrhages found in the lymphoid organs during this disease. Virus replication has been observed in the epithelial cells, fibroblasts and reticular cell beginning on day 5 post-infection. The activation of the endothelial cells, apoptosis of lymphocytes, decreased lymphocyte mitosis and virus replication in non-mononuclear phagocyte system (MPS) cells all occurred after an intense proliferation and activation of the tonsillar macrophages and coincide with virus replication, which occurs in the macrophages 5 days post infection.

The morphological changes in platelets in acute and subacute African swine fever (ASF) and their relationship to pathogenesis were studied. Eight pigs were inoculated with a highly virulent strain of African swine fever (Malawi '83) and 14 with a moderately virulent strain (Dominican Republic '78) for ultrastructural study of platelets, monocyte/macrophages and vascular structures in the liver, spleen, lymph node, bone marrow, lung and kidney. Both viruses produced activation and degranulation of platelets from day 3 after inoculation onwards, coinciding with activation of the mononuclear phagocyte system and virus replication in monocyte/macrophages. Platelet aggregation and viscous metamorphosis of platelets were observed at 5 and 7 days after inoculation with the highly virulent strain, coinciding with endothelial alterations, but platelet aggregation was less prevalent and there was no sign of viscous metamorphosis in animals inoculated with the moderately virulent strain. Virions within platelets were observed at the final stage of acute ASF and at 5-7 days after inoculation in subacute ASF. This suggests that platelets assist in disseminating ASF virus within the body, especially in subacute infections.

Recent studies of pulmonary intravascular macrophages have led to the re-examination of the mechanisms giving rise to alveolar oedema. A highly virulent isolate of African swine fever virus was replicated in pulmonary intravascular macrophages, interstitial and alveolar macrophages, fibroblasts and neutrophils. The alveolar oedema-characteristic of acute forms of African swine fever-and the vascular changes observed, which consisted of the formation of fibrin microthrombi in septal capillaries and the vacuolisation of endothelial cells, may have been due, however, to the activation of pulmonary intravascular macrophages, and not to the cytopathic effect subsequent to the replication of the African swine fever virus. Furthermore, it was observed that virus replication in cells not belonging to the mononuclear phagocyte system-such as fibroblasts and neutrophils-occurred earlier than in cells belonging to that system.

This paper reports apoptosis of lymph-node lymphocytes in swine experimentally inoculated with a virulent African swine fever (ASF) virus isolate (Malawi '83). Apoptosis was observed in both compartments of cortical tissue, but was more intense in diffuse lymphoid tissue (T area). Lymphopenia detected in peripheral blood was associated with T-lymphocyte depletion. No evidence of ASF virus replication was observed in lymphocytes in the lymph nodes studied. This finding, together with the high rate of virus replication recorded in macrophages in diffuse lymphoid tissue as compared with the low rate recorded for lymphoid follicles, suggests a mechanism for the induction of apoptosis related to virus replication in cells of the mononuclear phagocyte system.

The pathological effect of haemorrhagic fever viruses on the kidney have not been clearly documented. This study reports glomerular lesions in African swine fever. In the acute form of the disease there was an acute diffuse proliferative glomerulonephritis, which was believed to be related to virus replication in circulating monocytes and glomerular mesangial cells, and to the presence of abundant circulating cell debris resulting from viral replication at other sites. In the subacute form, the proliferative mesangial glomerulonephritis observed may have been associated with systemic immune-mediated phenomena, and with subendothelial and mesangial deposits of immunoglobulins and complement components.

The presence of virus replication centers in neutrophils from pigs inoculated with a highly virulent strain of African swine fever virus is described for the first time in vivo. Virus antigens were observed from 3 days post-inoculation (dpi) onwards by means of an immunohistochemical technique. At this time (3 dpi), transmission electron microscopy studies revealed the presence of large amounts of neutrophils in the vascular lumens. At 5 and 7 dpi, neutrophils with phagosomes frequently contained virus particles. In addition, within the cytoplasm of some mature and immature neutrophils, both viral particles and virus replication centers were observed at 5 and 7 dpi.

This paper reports the presence of mature viral particles within the lymphocytes of samples taken from pigs inoculated with a highly virulent African swine fever (ASF) virus isolate (Malawi 83), and the adhesion of the lymphocytes to macrophages containing the virus replication sites. Virus replication in lymph-node medullar tissue macrophages was observed from 3 days post inoculation (pi). At 3 days pi, transmission electron microscopy revealed hemadsorption in some infected macrophages. At 5 and 7 days pi, a number of macrophages with virus replication were surrounded by a ring of lymphocytes. In such cases, mature viral particles were observed in membrane evaginations of the infected cell that corresponded to invaginations of the lymphocyte membrane. Also at 5 and 7 days pi, mature virions were observed within the cytoplasm of some lymphocytes. However, incomplete virions and African swine fever virus replication sites were not observed within the lymphocytes.

In order to determine the cause of cellular death of lymphocytes in pigs with acute African swine fever and the relationships between African swine fever virus (ASFV) and interstitial cells, ten pigs were inoculated with a highly virulent strain of ASFV (Malawi '83) and samples taken for ultrastructural study of hepatic and renal interstitial tissues. We demonstrated death by apoptosis of lymphocytes and virus replication in fibroblasts, smooth muscle cells and endothelial cells in the interstitial tissues of pigs inoculated with ASFV. From day 5 onwards, apoptotic lymphocyte and intense virus replication in hepatic interstitial macrophages and fibroblasts were observed. By day 7, apoptotic lymphocytes and virus replication in macrophages, interstitial capillary endothelial cells and fibroblasts in the kidney were observed. Virus replication was also seen in smooth muscle cells of hepatic and renal arterioles and venules. Our results suggest that mononuclear phagocyte system (MPS) cell activation, and the resulting release of cytokines, could induce apoptosis of lymphocytes and virus replication in non-MPS cells.

African swine fever is a viral disease of pigs characterized predominantly by haemorrhagic lesions. This paper reports the lesions observed in the renal interstitial capillaries of pigs inoculated with African swine fever virus strains of differing virulence: the Malawi'83 strain (haemadsorbent and highly virulent) and the Dominican Republic'78 strain (haemadsorbent and moderately virulent). In pigs infected with the Malawi'83 strain, petechial haemorrhages and microhaemorrhages were observed 5 days after inoculation and lesions were evident in the renal capillaries. Signs of phagocyte activation were noticeable in endothelial cells, with enlarged fenestrations and even loss of endothelium, leaving the basement membrane of the vessels exposed. Platelet plugs and microthrombi were also observed in these vessels. At 7 days after inoculation these lesions had intensified, and were accompanied by virus replication in the endothelial cells. In pigs infected with the Dominican Republic'78 strain, haemorrhages were more abundant and more extensive, and although no endothelial cell lesions were observed, there was intense vasodilation with diapedesis of erythrocytes.

The activity of several proteins involved in fibrinolysis and the morphological changes in the blood vessel walls of pigs infected with highly virulent (Malawi'83) and moderately virulent (Dominican Republic '78-DR'78) ASF virus isolates were determined. Pigs infected with the Malawi'83 virus developed an increased fibrinolytic activity due to high plasma levels of tissue-plasminogen activator (t-PA) of 71.3 +/- 22.8 IU/ml (mean +/- SD), which correlated well with an increased activation of interstitial capillary endothelial cells and high levels of 1150 +/- 73.6 nM of fibrin monomer in the circulation. Animals infected with DR'78 virus, in contrast, showed an inhibition of fibrinolysis in the late stages of disease with almost a 5-fold increase of plasminogen activator inhibitor (PAI) activity of 196.0 AU/ml. These results suggest that activation of the fibrinolytic system in pigs infected with the Malawi'83 virus is probably due to increased formation and deposition of fibrin in the circulation, contributing to an increased bleeding tendency and higher mortality. On the contrary, animals infected with DR'78 virus developed an inhibition of fibrinolysis and thus a reduction in bleeding.

Despite the considerable attention given to kidney lesions in African swine fever (ASF), a number of questions remain to be answered. Structural and ultrastructural examination showed that a highly virulent isolate of ASF virus (Malawi 83) replicated in glomerular mesangial cells and renal collecting duct epithelial cells, with hyperplasia of the latter in infected pigs. Replication in mesangial cells may be due to their contact with the bloodstream, as well as to their phagocytic capacity and high metabolism rate. Virus replication in macrophages and endothelial cells of interstitial capillaries, and the necrosis of these infected cells gave rise to a large number of free virus in interstitial tissue. This, together with the lesser thickness of the basal membrane of collecting ducts in comparison to the rest of the tubular system, probably facilitates ASFV infection of tubular epithelial cells. Virus replication in these cells may account for the presence of virus in the urine of pigs with acute ASF where haematuria is not observed.

A 55 kilobase pair (kb) region from the right end of the virulent African swine fever virus isolate, Malawi LIL20/1, has been sequenced. The 68 major open reading frames (ORFs) encoded are generally closely spaced and read from both DNA strands across the complete sequence. Comparison of the amino acid sequences of predicted ORFs with sequence databases identified 15 ORFs which encode proteins that are similar to proteins of known function. Two ORFs are homologous to copies of multigene family 360 (MGF360) and one ORF is homologous to copies of multigene family 110 (MGF110). Both of these multigene families have been described previously.

We studied the evolution of shock using a comprehensive array of haematological tests in pigs infected with the highly virulent strain Malawi '83 (Lilongwe 20/1). A sudden onset of illness was observed between day 5 and 7 after inoculation with development of flush, episodes of epistaxis and melaena. Prior to these clinical signs, initiation of a consumption coagulopathy was demonstrated with loss of antithrombin III and plasminogen activity. Our findings indicate that during infection with this highly virulent strain the development of a consumption coagulopathy precedes and possibly contributes to shock, which results in haemorrhage and death.

African swine fever (ASF) virus strains cause haemorrhage by producing a variety of defects, which vary in severity from strain to strain. To distinguish the main haemostatic defects leading to haemorrhage, two groups of pigs were infected with moderately virulent (Dominican Republic '78) and less virulent (Malta '78) ASF virus strains. Mortality rate and severity of clinical observations were greater in pigs infected with DR '78 virus compared with pigs infected with Malta '78 virus. The animals became febrile from day 3 to 4 onwards at a time when the viraemia was high (10(7) to 10(8) HAD50/ml). No difference was found during the period observed in their pattern of viraemia or pyrexia. Thrombocytopenia developed in both groups but with different kinetics, suggesting two different mechanisms of sequestration of platelets. When coagulation tests were performed, significant abnormalities were found, including evidence for disseminated intravascular coagulation. These abnormalities were much less pronounced in the group infected with Malta '78. Antithrombin III activity did not change significantly in either group. Decreased plasminogen activity was found in the early phase of disease in DR '78 infected pigs. These results indicate that when haemorrhage does occur in DR '78 infected pigs, it is a consequence of more pronounced degrees of haemostatic impairment probably due to a marked endothelial injury and/or generation of procoagulant activity.

Changes in eating habits and developments in food technology are occurring at the same time as an upward trend in foodborne infection in Britain. Vulnerable people such as the elderly and hospital patients are increasingly likely to consume food produced by new systems such as 'cook-chill' and 'cuisson sous vide'. The microbiological hazards of these systems are assessed as negligible, provided that production is controlled by appropriate methods such as the hazard analysis critical control point (HACCP) approach. The occurrence and control of bacterial contamination in a hospital cook-chill system is reviewed in this context.

Nucleotide sequencing identified a tandemly repeated sequence array 22 x 10(3) base-pairs from the right-hand DNA terminus of the African swine fever virus (ASFV) genome. The sequence of the repeat array and sequences closely flanking it were compared in the genomes of four groups of ASFV isolates that had very different restriction enzyme site maps. Arrays present in one group of ASFV isolates from East Zambia/Malawi varied in length and contained between 8 and 38 copies of a 17-nucleotide repeat unit. Repeat arrays in a second group of ASFV isolates from Europe were less variable in length but consisted of different types of repeat unit that were divergent in sequence. A third genetically diverse ASFV isolate. LIV 13 from a South Zambia Game Park, contained repeat unit types that were similar to those of European viruses. MFUE6 isolate from an East Zambia Game Park contained a shorter version of the European repeat unit. An eight-base-pair core sequence was conserved between the East Zambia/Malawi and European and LIV 13 repeat units. These tandemly repeated sequence arrays share a number of properties with chromosomal minisatellite DNA. Similar tandem repeat arrays have not been described in poxviruses.

Eleven children aged 7 to 8 years from one school class developed diarrhoea and vomiting after an educational visit to a dairy farm. Three required hospital admission and intravenous fluid replacement for dehydration. Cryptosporidium oocytes were found in the faeces of these three children and from one classmate when the remainder of the class was tested between 16 and 21 days after the visit. At the farm some children tasted pelleted cow feed, silage and dried milk powder. A case-control study showed a significant correlation between diarrhoea and the tasting of silage and pelleted feed. Guidance on the safe conduct of educational visits to farms is given.

Restriction enzyme site mapping showed that most BamHI and all ClaI sites were conserved on the genomes of 17 African swine fever virus isolates from separate disease outbreaks that occurred between 1982 and 1989 in Malawi. However, frequent variation between virus genomes did occur due to addition or deletion of DNA sequences at various positions along the genome and 11 virus genotypes could thus be distinguished among the 17 isolates analysed. Length variations occurred at 10 different loci on the virus genome. These variable regions were located between the left DNA terminus and a position up to 48 kb from that terminus, in the centre of the genome 90 to 93 kb from the left DNA terminus and between the right DNA terminus and a position 22 kb from that terminus. Length variations in most of these regions were small (less than 1 kb) but variations of about 4 kb occurred in a region up to 20 kb from the left DNA terminus.

No evidence for the presence of soft ticks of the Ornithodoros moubata complex was found during a survey of African swine fever carried out between 1985 and 1988 in the West Province and southern parts of the North West and South West Provinces of Cameroon. The survey consisted of interviews of veterinary assistants and farmers, distribution of a questionnaire and tick searches both manually and with carbon dioxide traps. The absence of warthogs (Phacochoerus aethiopicus) from these areas was also recorded.

The replication of virulent and attenuated strains of African swine fever virus (ASFV) was studied in pure cultures of swine macrophages. To ensure complete destruction of the macrophage monolayers about 50--100 times more virulent ASFV was needed than attenuated virus although both isolates could be used to establish persistently infected cultures. Interferon did not appear to influence virus yields from such cultures. Fluorescent and electron microscopy studies of infected macrophages suggested that the cycle of infection of the two isolates was different.

Pigs vaccinated with glutaraldehyde-fixed alveolar macrophages (AM) infected with African swine fever virus (ASFV) had an accelerated serological response after subsequent challenge and a slight reduction in levels of viraemia. Vaccination of pigs with detergent-treated infected AM produced no detectable serological response and no protection against homologous challenge. Guinea pigs were vaccinated with glutaraldehyde-fixed ASFV-infected cells, detergent-treated infected cells, detergent-treated infected spleen homogenate, purified ASFV or sonicated infected cells. Antibody was detectable by ELISA after vaccination with all preparations except the detergent-treated infected spleen vaccine. However, vaccination with purified ASFV or sonicated infected cells induced antibodies that were also strongly reactive in antibody-dependent cell-mediated cytotoxicity and complement-mediated lysis assays. If such antibodies are protective, immunization of pigs with purified ASFV or sonicated infected cells may induce a protective immunity.

The genomes of African swine fever virus isolates collected from soft ticks (Ornithodoros moubata) inhabiting warthog burrows in four areas of Zambia were compared by restriction enzyme site mapping. Isolates from different areas showed considerable diversity. The regions of genomes that differed between isolates were distributed throughout the virus genome, although some more conserved regions were identified, such as the right-hand third of the genome. The genomes of seven isolates from neighbouring warthog burrows within Livingstone Game Park in southern Zambia were more similar to each other than those from different areas. However, a number of differences were observed even between the genomes of isolates from the same warthog burrow. The variation between these latter isolates probably resulted from point mutations located at various positions along the genome, in addition to small additions or deletions at both terminal regions. Restriction enzyme site mapping indicated that one isolate may have originated by earlier recombination between two distinguishable viruses.

African swine fever (ASF) has been reported in the Eastern Province of Zambia since 1912 and is now considered to be enzootic there. A survey of the distribution of ASF virus in Zambia was carried out by virus isolation from Ornithodoros moubata ticks collected from animal burrows in National Parks and Game Management Areas in northern, eastern, central and southern Zambia. ASF virus was isolated from ticks in all areas examined. The prevalence of infection in O. moubata was between 0.4% in South Luangwa National Park and 5.1% in Livingstone Game Park and mean infectious virus titres ranged from 10(3.4) HAD50/tick in Kakumbe Game Management Area to 10(5.9) HAD50/tick in Chunga and Nalusanga Game Management Areas. The prevalence of infection in adult ticks was between 4.7% and 5.3% in all areas examined except Sumbu National Park and Livingstone Game Park, where the prevalence was 15.1% and 13.2% respectively in adult ticks. The ratio of infected females to males for all the infected adult ticks in all areas of Zambia was 3.2:1.

XY/XYY sex-chromosome mosaicism was demonstrated in both bone marrow and germ cells of a wild adult common shrew. Secondary sexual characteristics were those of a normal male, but the testes were small, and the sperm count was only about 3% of normal. Most of the seminiferous tubule cross-sections examined revealed serious spermatogenic impairment and a reduced diameter. A range of sex-chromosome pairing configurations was observed in XYY primary spermatocytes, including configurations involving the X and both Y chromosomes in a linear or radial array. The presence of metaphase II (MII) spreads with an XY sex-chromosome complement indicated that XYY primary spermatocytes could contribute products to MII. Following Burgoyne (1979) and Burgoyne and Biddle (1980), a number of models of spermatocyte loss were tested. The data indicated that there was an association between the sex-chromosome complement of primary spermatocytes and their contribution to MII. The best fit to the observed MII frequency data was provided by a model which assumed that all XYY primary spermatocytes with a univalent Y chromosome and a high proportion of XYY primary spermatocytes with an unpaired X chromosome failed to contribute products to MII.

Intraperitoneal immunization of pigs with anti-African swine fever virus (ASFV) antibody protected them against the effects of challenge with ASFV. This protection, which was exemplified by a reduction in pyrexia and viraemia plus an increased survival time, appeared to be mediated through the effects of complement-dependent antibody-mediated cytotoxicity (CDAC) or antibody dependent cell mediated cytotoxicity (ADCC). Experiments suggested that the reduction in viraemia was associated with complement lysis whereas protection was conferred by ADCC.

Food hygiene in British hospitals is reviewed in the context of national trends in food poisoning and changes in food legislation. New methods of large scale catering such as the cook-chill system are considered, and the safe operation of such a system in a typical health district is described. The application of current guidelines for the microbiological quality of cook-chill food is evaluated. The need for careful observance of these principles, together with appropriate microbiological surveillance of the process and the product, is demonstrated.

The immunological response of pigs infected with African swine fever virus was related to both quantitative and qualitative changes in the lymphocyte population. The cytolytic effect of the virus on lymphocytes caused a proportionally greater drop in B cell than in T cell numbers. A blastogenic test was developed to measure the appearance of specifically sensitised lymphocytes in the circulation. These appeared about 10 days after infection in animals infected with attenuated virus; pigs infected with virulent strains died before the appearance of this response.

African swine fever virus isolates were titrated in swine monocyte cultures established in microtitre trays. Although technically simpler and less laborious than conventional tube assays the microtitration assay was less sensitive, but for routine and comparative titrations offers distinct advantages.

Pivmecillinam (FL 1039) is the pivaloyloxymethyl ester of mecillinam (FL 1060) which has considerable in vitro activity against Enterobacteriaceae. 38 hospital inpatients who had proven urinary tract infections were treated with 400 mg pivmecillinam four times daily for 5-7 days. The MIC of mecillinam to the infecting organisms was determined as were the serum and urinary concentrations of the antibiotic. The patients were followed up for 4-6 weeks after the end of treatment. Three patients were lost to follow-up. Of the 35 patients who were adequately followed up, 29 (83%) were classified as cured and there were 6 failures. Reported side effects were of a minor nature.