Hematology and serum biochemistry values of trapped, healthy, free-ranging rock hyraxes (Procavia capensis) and their association with age, sex, and gestational status

BACKGROUND: The rock hyrax (Procavia capensis) is an herbivore prevalent from South Africa to Turkey, and a most common zoo animal. Although many studies of hyrax diseases and physiology are available, clinicopathologic data are limited. OBJECTIVES: The purpose of this study was to establish comprehensive hematologic and biochemical reference intervals for trapped, apparently healthy, free-ranging rock hyraxes using modern laboratory methods and to assess differences related to sex, gestation, and age. METHODS: Blood samples were obtained from 27 healthy, free-ranging hyraxes under anesthesia. Gender, body weight, and gestational status were recorded. Hematologic (n = 25) and serum biochemical (n = 22) analyses were performed using standard automated methodology. Data for male vs female, adult vs juvenile, and pregnant vs nonpregnant female hyraxes were compared using the Mann-Whitney U-test. Associations between variables were assessed using Pearson's or Spearman rank correlation tests. RESULTS: Significant age- and sex-related, but not gestation-related differences were observed in several variables. Serum alkaline phosphatase activity and phosphorus concentration were significantly higher in juveniles compared with adults. A unique type of monocyte comprised 1-3% of leukocytes in 4 hyraxes. Markedly high serum creatine kinase (CK) activity was observed in most hyraxes. CONCLUSIONS: The large number of animals and the availability of sex, age, and gestational data in this study will be useful to zoo and wildlife veterinarians working with rock hyraxes. High serum concentrations of betahydroxybutyric acid in the rock hyrax, compared with dogs, cats, and ruminants, may be related to its unique digestive system. High CK activity may have been the result of a capture myopathy-like syndrome. The unique monocytes in hyraxes resemble those of elephants and are a novel finding in this species.     

Relationships between clinical signs, pathological changes and tissue distribution of Mycobacterium avium subspecies paratuberculosis in 21 cows from herds affected by Johne's disease

Twenty-one cows from eight herds affected by Johne's disease were assigned to four groups: seven were not thriving and had persistent diarrhoea, six were not thriving and had intermittent diarrhoea, four were not thriving but did not have diarrhoea, and four were clinically normal. Postmortem, macroscopic lesions consistent with Johne's disease were identified in 17 of the cows and Mycobacterium avium subspecies paratuberculosis (MAP) was isolated from all of them. However, except for the fact that diarrhoea was correlated with the presence of lesions in the large intestine there was little correlation between the presence or absence of clinical signs and the lesions associated with Johne's disease. The tissue distribution of MAP was also poorly correlated with either the clinical signs or the lesions. The organism was widely distributed in 17 of the 21 cows, including three of the clinically normal animals, and was present in the mammary tissues of seven cows including two of the clinically normal animals. Three distinct histopathological patterns were observed in the affected intestines: infiltration of the lamina propria with giant cells, tuberculoid lesions, and lepromatous lesions; the lepromatous lesions were associated with extensive pathological changes.     

Pancreatic islet fibrosis in rock hyrax (Procavia capensis), Part 2: Pathology, immunohistochemistry, and electron microscopy.

Pancreatic islet fibrosis with varying degrees of islet cell hyperplasia or islet effacement was diagnosed histologically in 19 rock hyraxes (Procavia capensis) from seven zoological parks. Some, but not all, affected hyraxes were from a common lineage. The condition was associated with apparent hyperglycemia in seven and diabetes mellitus in two. Immunohistochemistry revealed hyperplasia of beta, alpha, and delta cells proportional to the degree of the fibrosis. Electron microscopy revealed collagen deposition and fibroplasia within and around the islets. Special stains and electron microscopy were negative for the presence of amyloid. Beta cell depletion was never identified. The condition has morphologic features that resemble islet fibrosis of human infants born to diabetic mothers.     

Acute and chronic oxalate toxicity in Miniature Horses associated with soursob (Oxalis pes‐caprae) ingestion

Over the period of 11 years (2004–2015) 14 miniature horses in six separate outbreaks presented with clinical signs consistent with acute or chronic oxalate toxicity. All animals had access to Oxalis pes‐caprae or soursob. Miniature horses with acute oxalate toxicity and hypocalcaemia had muscle fasciculations, tremors and synchronous diaphragmatic flutter; these horses responded to treatment with intravenous and oral calcium. Chronic oxalate toxicity was associated with ill‐thrift, stiffness, enlarged heads, kyphosis and neurological signs. These animals had normal serum calcium concentrations, but increased serum alkaline phosphatase activity. Radiographs indicated that affected animals had bones that were osteopenic, often with pathological fractures. Bones that were examined histologically showed increased osteoclastic and osteoblastic activity, consistent with nutritional secondary hyperparathyroidism and fibrous osteodystrophy. These animals were treated, with mixed success, with oral calcium supplementation. A palatability trial showed that horses will readily eat soursobs, and measured total oxalate concentrations in soursobs collected from five different properties ranged from 13.5 to 18.5%. The presentation of affected animals with either acute hypocalcaemia or nutritional secondary hyperparathyroidism, together with a history of grazing soursobs, suggest that acute and chronic oxalate toxicity are the cause of the clinical signs seen in affected miniature horses.     

Use of electromyography for the diagnosis of equine hyperkalemic periodic paresis.

The use of electromyography (EMG) as a diagnostic aid for equine hyperkalemic periodic paresis (EHPP) was investigated in seven affected and seven control horses. Affected horses were confirmed positive for EHPP either by elevated serum potassium concentration with clinical signs of myotonia, or by inducing hyperkalemia and clinical signs using oral potassium chloride challenge. All horses were asymptomatic at the time EMG was performed, using bipolar fine wire needle electrodes. The myopotentials were recorded on magnetic tape and displayed on paper charts for analysis. Insertional and resting activity were recorded from the right supraspinatus, triceps, extensor carpi radialis and gluteal muscles in standing horses. Myotonic discharges were seen in six of seven affected horses but not in any of the controls. All seven affected horses and two control horses had prolonged insertional activity. Five out of seven affected horses and one control horse displayed spontaneous motor unit discharges unrelated to recording electrode movement. Myoelectrical potentials containing closely timed muscle potentials, i.e. doublets, were found in all affected horses, with four of seven affected horses also showing triplets. These potentials were not observed in any of the controls. No obvious difference in activity was observed among the four muscle sites tested. It is concluded that EMG is a safe and useful tool for diagnosing EHPP in horses not currently displaying clinical signs. Myotonic discharges and doublets appear to be the most diagnostically significant electromyographic abnormalities in EHPP affected horses.     

Controlling tuberculosis in a llama (Lama glama) herd using clinical signs, tuberculin skin testing and serology

An outbreak of tuberculosis (TB), caused by Mycobacterium bovis, was investigated in a small herd of llamas (Lama glama). Based on three ante-mortem diagnostic methods (clinical signs, tuberculin skin test reactions, and 'Rapid Test' serology), 12 llamas were selected for examination post-mortem. Grossly visible lesions suspicious of TB were observed in eight animals, four of which had exhibited clinical signs, one was a skin test 'reactor', and three had been seropositive. M. bovis was isolated from seven of these eight animals. Clinical signs combined with serology were found to be useful in identifying infected animals, but tuberculin skin testing had limited negative predictive value as four llamas that were subsequently confirmed as infected were not detected using this assay.     

Dermatophytosis in red pandas (Ailurus fulgens fulgens): a review of 14 cases.

Fourteen cases of dermatophytosis were identified from medical records of red pandas (Ailurus fulgens fulgens) housed at the Knoxville Zoo between 1980 and 1996. The median age of affected animals on initial presentation was 8.5 wk (3 wk-11 mo). Clinical signs included crusting, purulent exudate, alopecia, thickening of affected skin, ulceration, and necrosis. Seven animals had mild lesions with signs restricted to crusting and/or alopecia, and six animals had more severe infections, with ulceration, skin necrosis, and purulent exudate. Five of the severely affected pandas had tail involvement. The severity of disease affecting one individual was not recorded. Dermatophytosis was confirmed by culture, cytology, histopathology, or culture followed by histopathology. Microsporum gypseum was the only fungal organism cultured. Six animals were treated for mild disease, and all clinical signs resolved. Partial tail amputation was required as part of the treatment regimen for two of the six severely affected animals, and two others had ulcerated tail lesions that left circumferential scarring after resolution of infection. Itraconazole (5 mg/kg p.o. q 12-24 hr) was the most frequently used systemic antifungal agent in animals with severe lesions. All fungal infections resolved, although one panda died from unrelated causes early in the treatment period.     

CLINICAL AND MAGNETIC RESONANCE IMAGING FEATURES OF IDIOPATHIC OCULOMOTOR NEUROPATHY IN 14 DOGS

Ophthalmoplegia/ophthalmoparesis (internal, external, or both) has been reported in dogs secondary to neoplasia affecting the oculomotor nerve and is usually given a poor prognosis. The purpose of this retrospective study was to describe the clinical findings, magnetic resonance imaging (MRI) findings, management, outcome, and follow‐up in a group of canine cases with idiopathic oculomotor neuropathy. Inclusion criteria included cases with ophthalmoplegia/ophthalmoparesis (internal, external or both) as sole neuroophthalmologic signs, complete ophthalmic and neurologic examination, head MRI, and a minimum follow‐up period of 1 year. Dogs with progressive neurological signs not related to oculomotor neuropathy were excluded. Fourteen cases met the inclusion criteria. All cases were unilaterally affected. Magnetic resonance imaging showed equivocal enlargement of the oculomotor nerve in three cases, mild enlargement in five, and marked enlargement in six. Contrast enhancement was present in 12 cases, being marked in six. When present, the contrast enhancement was focal in eight cases and diffuse in four. The median follow‐up time was 25 months. External ophthalmoparesis improved in seven cases, five cases under no treatment and two under systemic corticosteroid therapy. The clinical signs in the other seven cases remained unchanged. Idiopathic oculomotor neuropathy should be included as a differential diagnosis in dogs presenting with unilateral ophthalmoplegia/ophthalmoparesis (internal, external, or both) with the absence of other neurologic and ophthalmic signs, and with the MRI findings restricted to the oculomotor nerve. Idiopathic oculomotor neuropathy has a good prognosis as the clinical signs do not deteriorate and they can improve without treatment.     

Ostertagiasis in calves. II. infection parameters and body weight gains following housing

The performance of six groups of six calves each from a previous field experiment was followed from the beginning of housing until turning out seven months later. When housed the groups harboured different levels of infection with Ostertagia ostertagi and had corresponding weight and gain reductions. The most heavily infected groups improved rapidly following housing. Elevated serum pepsinogen levels decreased markedly, and approached normal values at eight weeks. Differences in serum pepsinogen levels between groups diminished considerably, but remained significant over the entire stabling period. The serum albumin level was low in the most seriously affected animals at the time of housing, but normal levels were restored within the first twelve weeks. In general, the number of parasite eggs in the faeces of the animals decreased, but there was considerable fluctuation. Apart from a single sampling date, no significant difference in egg per gram (EPG) could be demonstrated between the experimental groups during the stabling period.The calves were fed according to their age. The live weight differences between most and least affected groups diminished from 64 kg at the time of housing to 37 kg at the end of the stabling period. The reduction took place particularly during the first four weeks of housing.Considering both the grazing and stabling periods, it appeared that anthelmintic treatment twice during the period had no effect on the final live weight, whereas remeated treatments at three-week intervals resulted in an increase of 24 kg. Similarly, moving the animals to a clean pasture in mid-July resulted in an increase of 39 kg at the end of the stabling period when compared to calves which were not moved. Treatment of moved animals did not result in further body weight gain after seven months of housing.No significant correlation was found between parasite EPG of faeces and growth rate during the stabling period. However, a positive correlation was found between serum pepsinogen during the first eight weeks of housing and the weight gain over the entire stabling period. This was in contrast to the correlation experienced during the grazing period.     

Clinical course of pyruvate kinase deficiency in Abyssinian and Somali cats

The objective of this study was to examine clinical signs, laboratory parameters, and course of disease in Abyssinian and Somali cats with pyruvate kinase (PK) deficiency. The clinical course of 25 PK-deficient cats was followed over a time period of 0.8-11.3 years (median 4.3). Eleven cats (age 0.8-7.8 years, median 4.4) did not show signs according to the owners. In 14 cats (age 0.1-5 years, median 1.7) the owners noted lethargy (10), diarrhoea (seven), pale mucous membranes (six), inappetence (six), poor coat quality (six), weight loss (four), icterus (four), and pica (two). Sixteen cats had been used for breeding at least once before diagnosis. Laboratory abnormalities included anaemia (70%), increased aggregated reticulocyte counts (94%), hyperglobulinaemia (80%), hyperbilirubinaemia (53%), and increased liver enzymes (47%). Six of 25 affected cats died (four) or were euthanased (two) at ages ranging from 1.3 to 11.3 years (median 4.1) presumably because of PK-deficiency. These findings emphasise that PK deficiency shows variation in age of onset and severity of signs. As PK-deficient cats can be asymptomatic testing for PK deficiency before breeding is strongly recommended.     

Ultrasonographic diagnosis of congenital portosystemic shunt in 14 cats

Twenty-four cats with clinical and, or, clinico-pathological signs compatible with portosystemic shunting were examined prospectively using two-dimensional grey-scale, duplex and colourflow Doppler ultrasonography. Diagnosis of congenital portosystemic shunt was subsequently confirmed in 14 cats using operative mesenteric portography and surgery. Of the 14 affected cats, nine were purebred; eight were male and six female. The mean age at the time of diagnosis was nine months (range four to 27 months). Ultrasonographic evidence of a small liver was present in seven cats (50 per cent); visibility of intrahepatic portal vessels was reduced in three (21 per cent). An anomalous blood vessel was identified ultrasonographically in each cat; in 10 cats (71 per cent) the vessel was observed to originate from the portal vein and drain into the caudal vena cava. Abnormally variable portal blood flow waspresent in eight of the 10 cats in which it was measured. At surgery, six shunts were intrahepatic and eight extrahepatic; the ultrasonographic diagnosis of intra- versus extra-hepatic shunt was correct in 13 cats (93 per cent). No anomalous blood vessels or abnormalities affecting the portal vein were detected ultrasonographically in any of the 10 cats that did not have congenital portosystemic shunting. Hence, the accuracy of ultrasonography for diagnosis of congenital portosystemic shunting in this series was 100 per cent.     

Scintigraphic and radiographic evaluation of appendicular skeletal lesions in cold-stunned Kemp's ridley sea turtles

Osteolytic appendicular skeletal lesions in eight-stranded, cold-stunned Kemp's ridley sea turtles (Lepidochelys kempii) were evaluated using radiography and skeletal scintigraphy. Radiographic studies were performed monthly in most animals. Follow-up scintigraphy was performed 45-120 days after the initial exams in six turtles. Radiographically, lesions slowly progressed from an early osteolytic process contained to either the proximal or distal end of long bones, to a later stage characterized by thickening of the affected bone, sclerosis, and remodeling of the lesion borders. In seven turtles, the initial scintigrams were characterized by at least one focus of abnormal radiopharmaceutical uptake that correlated with a lytic site noted in radiographs. In five turtles, scintigraphic lesions were characterized by asymmetric radiopharmaceutical uptake rather than by increased intensity of uptake. Scintigraphic studies obtained more than 4 months after the appearance of clinical and radiographic signs had minimal, if any, abnormal radiopharmaceutical uptake, despite the persistence of abnormal radiographic findings. Skeletal scintigraphy is an effective method for more precisely determining if and when these animals can be returned to the wild. Animals were released if normal radiopharmaceutical uptake was seen during initial examination, or if decreased uptake was noted between serial examinations. In four of the turtles, resolution of abnormal scintigraphic findings permitted an objective decision to discontinue antibiotic and antifungal therapy. Seven of the eight turtles were released after correlation of the clinical signs with the imaging findings. Radiographs, however, are still needed to facilitate the correct identification of lesions with scintigraphy.     

Aspects of the metabolism of dairy cows during the incubation of bovine spongiform encephalopathy

As part of a nutritional study lasting from six weeks before calving to 22 weeks of lactation, blood samples collected from 47 dairy cows maintained under well-defined conditions were analysed for a variety of metabolites and hormones. At various times after the completion of the study, six of the animals developed clinical signs of bovine spongiform encephalopathy (BSE), although when they were sampled it was not known that they were incubating the disease. The data were used to make comparisons between the animals that developed BSE and those that did not develop the disease and which had been maintained under the same conditions. The greatest differences between the animals incubating BSE and the control animals were observed at times of nutritional stress, at the start of lactation and when the intake of concentrate feeds was reduced at week 13 of lactation. In the animals that subsequently developed BSE, feed intakes were lower in early lactation; plasma beta-hydroxbutyrate concentrations were significantly higher (P<0.001) at weeks 3 and 5 of lactation; adjusted milk yields were lower until week 6 of lactation and milk fat concentrations were consistently lower. There was no effect on plasma glucose concentrations, although insulin concentrations were significantly lower in week 1 of lactation (2-27 v 2.50 microiu/ml) (P<0.05). The concentrations of plasma proteins and urea were unaffected by BSE incubation, apart from protein concentrations being significantly higher one week before calving, and the concentration of urea being significantly lower five weeks before calving. The plasma concentrations of somatotrophin, prolactin, oestradiol and progesterone were similar in the two groups of animals throughout the study. The differences observed indicate that the energy metabolism of dairy cows incubating BSE may be subtly altered before the onset of clinical signs of the disease.     

Surgical castration and the effect on aggression in rock hyrax (Procavia capensis).

Lincoln Park Zoo acquired five intact, male rock hyraxes (Procavia capensis) from three separate institutions to exhibit as a group. The animals were of varying ages at the time of acquisition. During quarantine, all five were surgically castrated via a midline laparotomy technique in an attempt to reduce expected aggression within the group. Recommendations for successful castration, based on these five procedures, include performing the procedure on sexually immature hyraxes or sexually inactive adults, the use of a second surgeon during the procedure, and the use of stainless steel surgical clips for ligation of vessels and spermatic cord. Although combinations of the castrated animals coexisted for longer periods than those documented for other nonrelated male groups, aggression was significant and resulted in the death of one individual. Ultimately, all animals were housed individually.     

Lymphocyte transformation and humoral immune factors in Basenji dogs with immunoproliferative small intestinal disease

Serum protein concentrations and 4 immunologic factors were determined in 5 Basenji dogs with immunoproliferative small intestinal disease. There was no correlation between the total serum proteins, immunoglobulin G and immunoglobulin M concentrations, and physical health status of the animals. The severity of clinical signs correlated roughly with decrease in albumin and increase in globulin concentrations. The main changes were detected in beta- and fast gamma-globulins. The total hemolytic complement levels were decreased in the 2 most severely affected animals below the minimal laboratory values observed in healthy animals. Alteration in the intrinsic responsiveness of lymphocytes to various mitogens did not correlate with progression in severity of the disease. Correlation between the appearance of blastogenesis-suppressing substances in serum and the severity of the disease was only partial: Sera (at 20% concentration) from the 2 most severely affected dogs completely suppressed blastogenesis induced by all 3 mitogens. The sera of 3 other dogs either did not suppress or suppressed only concanavalin A-induced mitogenesis and to a lesser extent phytohemagglutinin-induced mitogenesis without correlations to the overall clinical status. The disturbances of immunologic mechanisms were detected after the appearance of clinical disease, were not considered the cause of immunoproliferative small intestinal disease, may represent a manifestation of the secondary infection, and may contribute to aggravation of the clinical course.     

Reemergence of Dourine in Italy: Clinical Cases in Some Positive Horses

In 2011, Trypanosoma equiperdum reemerged in Italy, almost 10 years after its last appearance. A total of eight infected horses have been observed to date. Six horses were affected by natural outbreaks of the disease, whereas two were infected experimentally. The aim of this study was to offer a recent perspective on clinical cases of dourine in Europe. Investigation of the clinical aspects confirmed the three stages reported in the literature: stage 1 (genital lesions), stage 2 (cutaneous signs), and stage 3 (nervous signs). The most common signs in the horses under study were notable weight loss, edematous skin eruptions and oedemas of the abdomen, mammary glands and hind legs. Three animals presented neurological signs (lip ptosis of lower lip and ataxia). Infections were paucisymptomatic or asymptomatic in some animals. Hyperthermia was not reported in infected animals and considerable anemia was observed. High antibody titers did not always correspond to clinical signs. Positive polymerase chain reaction test results of blood or tissue (skin, eye swab) often correspond to an advanced stage of the disease. Dourine is a variable disease; owing to its low prevalence and chronic manifestation, it can be difficult to make a quick diagnosis when facing a Dourine-positive horse.     

Equine laryngeal hemiplegia part II: Some clinical observations

Some clinical features of laryngeal hemiplegia in 127 horses are described. Possible aetiologic factors were found in only 11% of affected animals. The onset of clinical signs was either sudden or insidious. The majority of cases were presented because of an abnormal respiratory noise made at exercise. Other clinical signs, particularly those usually attributed to laryngopalatal dislocation, were observed in a substantial proportion of affected animals. In all cases surveyed the left arytenoid was affected, although in 3 animals a bilateral laryngeal dysfunction was noted. Thirty of 65 animals examined with a fibreoptic endoscope had other upper respiratory tract abnormalities in addition to abnormal arytenoid movements. Electrocardiographic examination of 45 affected horses did not reveal a significantly higher incidence of abnormalities than that observed in the racing population. The majority of haemograms taken from affected animals were also within normal limits.     

Equine laryngeal hemiplegia part II: some clinical observations

Some clinical features of laryngeal hemlplegia in 127 horses arc described. Possible aetiologic factors were found in only 11% of affected animals. The onset of clinical signs was either sudden or insidious. The majority of cases were presented because of an abnkmal respiratory noise made at exercise. Other clinical signs, particularly those usually attributed to laryngopalatal dislocation, were observed in a substantial proportion of affected animals. In all cases surveyed the left arytenoid was affected, although in 3 animals a bilateral laryngeal dysfunction was noted. Thirty of 65 animals examined with a fibreoptic endoscope had other upper respiratory tract abnormalities in addition to abnormal arytenoid movements. Electrocardiographic examination of 45 affected horses did not reveal a significantly higher incidence ot abnormalltles than that observed in the racing population. The majority of haemograms taken from affected animals were also within normal limits.     

Experimental myopathy in vitamin E- and selenium-depleted calves with and without added dietary polyunsaturated fatty acids as a model for nutritional degenerative myopathy in ruminant cattle

Fourteen calves, 14 weeks old, fed a low vitamin E and selenium diet based on sodium hydroxide-treated, selenium-deficient barley showed a rapid decline in plasma alpha-tocopherol, a gradual decline in erythrocyte glutathione peroxidase (GSHPX) activity, elevated plasma creatine kinase (CK) activity, teeth grinding and (in three cases) electrocardiographic changes, but no clinical abnormalities after 127 to 137 days. Necropsy of six depleted calves at that stage revealed pale muscles in two animals and mild histopathological lesions of skeletal myopathy in all six calves. Ten control calves were fed a similar diet supplemented with alpha-tocopherol and selenium. Plasma alpha-tocopherol and erythrocyte GSHPX activity remained high in these calves and no clinical abnormalities or evidence of myodegeneration were observed. When protected linseed oil was fed as a source of polyunsaturated fatty acids to the remaining eight depleted calves, rapid elevations in plasma CK activity and linolenic acid associated with a variety of cardiopulmonary and locomotory signs, electrocardiographic changes and myoglobinuria occurred within six to 11 days. Necropsy revealed widespread severe skeletal myodegeneration (eight calves) and myocardial lesions (five calves) with preferential involvement of the left ventricular myocardium. Clinical signs and pathological changes were similar to those reported in field outbreaks of nutritional degenerative myopathy in ruminant cattle and establish the experimental regime as the first successful model for reproduction of this disease.     

Citrinin as a possible cause of the pruritis, pyrexia, haemorrhagic syndrome in cattle

An outbreak of the pruritis, pyrexia, haemorrhagic syndrome affected eight of a herd of 175 cows which was divided into two groups of 115 and 60 according to yield. There was no difference in management between them but citrus pulp pellets were fed only to the larger group in which the eight cows were affected. Silage, which had been made without the use of additives, was also fed to both groups. The citrus pulp was visibly mouldy and contained 30 to 40 parts per billion of citrinin. Signs of the syndrome occurred within three days of the cows starting to ingest the citrus pulp, which was fed for 21 days, and the last case occurred six days after the feeding of citrus pulp ceased. Five calves whose dams had been fed citrus pulp were subsequently born with superior prognathism. In contrast to the eight cows that developed the syndrome only one out of 68 heifers which were fed larger quantities of citrus pulp for 10 days developed mild signs of the syndrome and then recovered, suggesting that older animals may be more susceptible. The clinical signs, gross pathology and histopathology are described and compared with those of previous outbreaks. Mycotoxins, particularly citrinin, were strongly implicated as the cause of this outbreak.