Outbreak Of Footrot Research Articles

Molecular detection and pathological investigations on southern blight disease caused by Sclerotium rolfsii on cabbage (Brassica oleracea var. capitata): A new record in India

AbstractA severe outbreak of foot rot and head rot disease of cabbage was observed during September 2017 to November 2019 in major cabbage growing regions of southern Karnataka state of India. The disease incidence ranged between 3% and 28%. The initial symptoms were observed as tan, water‐soaked lesions at the point of infection and development of mycelia, followed by quick wilting of the whole plant. Subsequently, numerous sclerotia were produced. The pathogen isolated on PDA medium produced white fluffy aerial mycelia and numerous reddish‐brown sclerotia after 7−10 days. A total of 18 fungal isolates were used for mycelial compatibility analysis. Isolate SrBoC28 was used to test for pathogenicity on cabbage, marigold, chilli and brinjal plants. Typical disease symptoms on leaves, stem and roots were evident 5, 8 and 10 days’ post‐inoculation respectively. The isolate was pathogenic on all tested hosts, and the identity was confirmed by re‐isolation and morpho‐cultural and molecular studies. The latter were based on amplification of ITS‐rDNA and phylogenetic analysis which showed 100% sequence similarity with reference sequences. The identity was confirmed as S. rolfsii. This is a well‐known pathogen and causes disease on various economically important crop plants. To date, there are no reports on the association between S. rolfsii and foot and head rot disease of cabbage in India and elsewhere. Thus, to the best of our knowledge, this is the first report of foot rot and head rot of cabbage caused by S. rolfsii in India.

Black Pepper in Malaysia: An Overview and Future Prospects

Cultivating black pepper in Malaysia started in early 10th to the 11th century when the South Indian Kings began to extend their empire. The crop was brought to East Malaysia in 1840 by Chinese settlers, actively planted until it was hit by the massive flood, fluctuation of the price and outbreak of foot rot. High yielding cultivars such as Kuching, Semenggok Emas and Semenggok Aman provided promise for better production, but resulted in increased soil degradation and reduced crop growth in Sarawak. The paper aims to discuss the black pepper industry in Sarawak and present scenario of its cultivation including future prospects. Cultivating on hilly topography with coarse textured dominant soil becomes one of the limiting factors. This factor is observed due to high rainfall intensity and steeper slopes. Neglected soil conservation also affects crop production and lead to a lower return on investments. Technologies such as land conservation and practising precision agriculture need to be adopted to reduce the impact of soil degradation and better production.

Outbreak of severe foot rot associated with benign Dichelobacter nodosus in an Alpine ibex colony in the Swiss Prealps.

An outbreak of foot rot occurred in the ibex colony "Vanil Noir" in Switzerland from May to December 2014. This article describes field observations and the analyses carried out on the limbs of 3 animals submitted for postmortem examination. Disease signs observed in the field included lameness, poor body condition and overgrown hooves. Macroscopic examination of selected limbs revealed severe lesions in all of them, including interdigital inflammation with ulceration and malodorous exudation. Histological changes were consistent with chronic laminitis with bone resorption, which was not detected at radiographical examination. Grocott-positive organisms compatible with Dichelobacternodosus were detected in the lesions. Samples collected from the lesions were positive by polymerase chain reaction for benign D. nodosus, which is typically associated with only mild lesions in domestic sheep. Whether D. nodosus is endemic in the colony or had previously been transmitted from sympatric domestic livestock is unclear. The unusual warm and humid weather conditions in 2014 may well have contributed to the outbreak.

Phylogenetic analysis of Dichelobacter nodosus serogroup-specific fimA gene from ovine footrot in Andhra Pradesh.

Aim:Identification of different serogroups of Dichelobacter nodosus prevailing in the region and to understand the degree of genetic heterogeneities among the different isolates of D. nodosus.Materials and Methods:A total of 150 exudate samples of footrot lesions with a lesion score of 2-4 were collected from naturally infected sheep. The samples were screened by polymerase chain reaction (PCR) targeting D. nodosus specific 16srRNA. Of 150 samples screened, 70 samples were found to be positive. The positive samples were attempted for isolation of D. nodosus, out of which 16 isolates were recovered. All the isolates were subjected to serogrouping by multiplex PCR targeting fimA gene using A-I serogroup specific primers.Results:Of 16 isolates, 7 (43.75%) isolates were serogroup B, 4 (25.00%) isolates were serogroup A, 3 isolates (18.75%) were serogroup I and 2 (12.5%) isolates yielded both serogroup A and B. phylogenetic analysis was performed using neighbor-joining algorithm of the ClustelX2 software in order to study whether the serogroups isolated in the present investigation differed genetically from other published serogroups. The fimA gene sequence of present isolates of serogroups A, B, and I were segregated into three distinct groups with high bootstrap values. The serogroup B clustered with Australian isolate of serotype B1 suggesting high genetic similarity of the present isolate with serotype B1.Conclusions:The clinical samples were collected from suspected outbreaks of footrot and identified the prevalence of D. nodosus by PCR targeting 16srRNA gene. Identified serogroups A, B, and I from different districts of Andhra Pradesh. The phylogenetic analysis will help for the tentative identification of serotypes present in the serogroup and to understand the degree of genetic heterogeneities among the different isolates of D. nodosus.

A recently introduced Dichelobacter nodosus strain caused an outbreak of footrot in Norway.

BackgroundIn 2008, an outbreak of ovine footrot occurred in Norway. Dichelobacter nodosus isolates collected between 2008 and 2011 have been characterised. Isolates defined as virulent by the gelatin gel test (GG-test) were only found in sheep in Rogaland County, where the severe cases of footrot were registered. The majority (96%) of the virulent isolates belonged to serogroup A. It is suspected that they represent a newly introduced strain, and the aim of the present study was to investigate whether they are genetically similar. Sixty-one virulent isolates from sheep and 116 benign isolates from sheep, cattle and goats were included. Four GG-test virulent isolates from Danish sheep were also included. All isolates were genotyped by pulsed-field gel electrophoresis (PFGE) and by PCR for pgr variant determination.ResultsThe Norwegian virulent isolates were assigned to 8 pulsotypes (PTs), while the benign isolates were assigned to 66 PTs. Thirty-seven (68.5%) of the 54, virulent, serogroup A isolates belonged to the same PT, and included isolates from 2008 through 2011. Isolates belonging to this PT were defined as the outbreak strain. The remaining virulent serogroup A isolates belonged to 4 PTs differing by ≤3 bands from the outbreak strain. Two virulent, Danish, serogroup A isolates differed by 2 bands from the Norwegian outbreak strain. All but 3 (95%) of the virulent isolates had the pgrA variant while 85% of the benign isolates had the pgrB variant.ConclusionThis study provides evidence that the footrot outbreak in Norway in 2008 most likely was caused by new introduction and local spread of one virulent D. nodosus strain.

Prevalence of ovine footrot in the tropical climate of southern India and isolation and characterisation of Dichelobacter nodosus.

The present communication records the first determination of the prevalence of footrot in the unexpected situation of the tropical climate of Andhra Pradesh and Tamil Nadu, two states in southern India where the maximum temperature rises to 42 degrees C. In total, 73 outbreaks of footrot in Nellore brown sheep were investigated in 11 districts of Andhra Pradesh and one district of Tamil Nadu during the period March 2009 to March 2011.The overall prevalence of ovine footrot was 15%, with severity scores of 2 to 4 (lesion severity scale 0 to 4). The outbreaks occurred mostly during the rainy season, which is usually from June to December. From a total of 1,050 samples of lesions in naturally infected sheep, 478 (45.5%) were positive for Dichelobacter nodosus. Serogrouping of the isolates revealed six serogroups: A, B, C, E, F and I. Among the positive samples, 448 (93.7%) were a single serogroup and 30 (6.3%) carried a mixed infection with two serogroups. Taking single and mixed infections together, serogroup B was most frequent at 50.4% and was found in all districts, followed by serogroup I in 29.3% of samples, A in 14%, F in 6.7% and C in 5.6%. Serogroup E was detected in only one sample. Serogroups A and F were detected for the first time in India. All of 58 D. nodosus isolates in a sub-sample representing different serogroups were found to be virulent, based on the production of thermostable proteases and the presence of the integrase A gene intA. Thus, the present paper reporting isolation and characterisation of D. nodosus confirms the occurrence of virulent footrot in the tropical climate of southern India.

Foot rot and other foot diseases of goat and sheep in the semiarid region of northeastern Brazil

This paper reports the occurrence and epidemiology of outbreaks of foot rot and other foot diseases in goats and sheep in the semiarid region of Paraíba, northeastern Brazil. Four farms were inspected for the presence of foot lesion in sheep and goats and for environmental conditions, general hygiene, pastures, and disease control measures. The prevalence of foot lesions was 19.41% (170/876) in sheep and 17.99% (52/289) in goats, ranging between 5.77% and 33.85% in different farms. Foot rot was the most common disease, affecting 12.1% of the animals examined (141/1165), but with significantly higher (p<0.05) prevalence in sheep (13.69%) than in goats (7.27%). The frequency of malignant foot rot was also significantly lower (p<0.05) in goats (9.53%) than in the sheep (40.83%). On one farm, Dorper sheep showed significantly higher (p<0.05) prevalence of foot rot (17.5%) than Santa Inês sheep (6.79%), and the number of digits affected was also higher in the former. Dichelobacter nodosus and Fusobacterium necrophorum were isolated from cases of foot rot. White line disease was found in 3.95% of the animals, sole ulcers in 1.29%, foot abscess in 1.03% and hoof overgrowth in 0.5%. The high rainfall at the time of occurrence, grazing in wetlands, clay soils with poor drainage, presence of numerous stony grounds, closure of the flocks in pens at night, and introduction of affected animals were considered predisposing factors for the occurrence of foot diseases.

PODODERMATITE INFECCIOSA EM OVINOS E CAPRINOS NO SERTÃO PARAIBANO

Foot rot is one of the most common foot diseases in goats and sheep. It is characterized by lameness, increased hoof sensitivity, interdigital dermatitis, and digital edema and necrosis. During the rainy season, there is an increase in body weight gain of animals due to the supply of good quality forage. It is also a time they are vulnerable to foot diseases. This study reports an outbreak of foot rot and other types of lameness in the semiarid region of Paraiba. Results revealed that 11,14% of animals presented typical virulent foot rot with underrunning lesions or benign foot rot with lesions limited to the interdigital skin. Goats and sheep of different breeds were affected by both forms of the disease. Other lesions observed included foot abscesses, sole ulcerations, pododermatitis, and abnormalities of hoof growth and development.

Recent footrot outbreak in Debrezeit swine farm, central Ethiopia

An outbreak of footrot has occurred in Debrezeit swine farm that is located 44 km south east of the capital. Among 24 pigs, 75% showed lameness, hot, painful and swollen feet, hemorrhagic bruising of the coronary band, heel erosion, sole ulcers and separation of skin from hoof on hind limbs. Bacteriological examination of the specimen from the affected limbs has shown the involvement of Staphylococcus, Streptococcus and Dichelobacter nodosus. The overt clinical lameness and inability to stand or mount can cause reduced reproductive performance. This preliminary finding thus warrants further epidemiological investigation.

Effect of climatic region on the clinical expression of footrot of lesser clinical severity (intermediate footrot) in sheep.

To determine if the clinical classification of intermediate footrot (IFR) is changed to virulent footrot (VFR) by a transfer of the infected flock to a region where climatic conditions are more favourable for the transmission of the disease. Clinical examination of two groups of Merino wethers infected with IFR; one group of 309 in a region considered less favourable for footrot and another group of 343 at a second site considered more favourable. After characterising the form of footrot at the first site, infection was established at the second site by mixing 142 wethers from the first site with 201 unrelated wethers considered to be free of IFR and VFR. Observations of clinical characteristics were made over a 16 month period during which an outbreak of footrot occurred. Clinical assessments were made by inspecting every foot of every sheep at regular intervals and allocating a footscore. Evidence that the same clonal lines of D. nodosus were responsible for the footrot at both sites was provided by serotyping of isolates and using omp gene RFLP as a molecular epidemiological tool. The disease at the first site was classified as IFR because 7% of the sheep developed a maximum footscore (MFS) of 4, the most severe category, despite relatively low rates of transmission. When the outbreak occurred at the second site, which was more suitable for footrot transmission, the maximum proportion of the flock that developed a MFS of 4 was 3.6%, confirming the initial classification of IFR. When a flock infected with IFR was moved to a region where climatic conditions were more favourable for footrot transmission, the clinical classification of the disease remained the same in both the original flock and in sheep exposed to the infection for the first time.

Benign footrot – an epidemiological investigation into the occurrence, effects on production, response to treatment and influence of environmental factors

Benign footrot was studied in 1 1/2-years-old Merinos on 2 farms in central Victoria from September 1987 to August 1990, inclusive. Treatment groups of 100 sheep grazed together with the remaining untreated sheep. Inspections were carried out every 3 weeks during the spring transmission period until the number of lesions greater than score 2 dropped below 3%. At each inspection, each sheep was weighed and lesion scores for each foot and digit were recorded, the treated group of sheep was treated by standing in 20% (w/v) zinc sulphate-sodium lauryl sulphate for 1 hour, and bacteriological samples were randomly collected from 5 sheep with and 5 without lesions. Dichelobacter nodosus organisms were obtained from sheep in both groups. Laboratory tests indicated benign organisms in flock A and low virulence, intermediate organisms in flock B. During the first 2 years, the number and severity of lesions were greater in flock A than in flock B. However, in the third year, with an early 'autumn break', there was a rapid and severe outbreak of footrot in flock B; 98% of the flock had lesions at the first inspection in July 1989. Flock A had a less dramatic increase in lesions of footrot. Both treated and untreated groups in flock B recovered rapidly between the third and fourth inspections. A later increase in lesions for both flocks coincided with damage caused by barely grass seeds. During this period there was a significant difference (P < 0.001) in body weight between the treated and untreated sheep on farm B.(ABSTRACT TRUNCATED AT 250 WORDS)

Microbiological study of foot-rot in lambs: isolation, elastolytic activity and antimicrobial susceptibility.

A microbiological study was made of an outbreak of foot-rot in lambs. Elastolytic activity was detected in all 10 Bacteroides nodosus strains isolated from the hooves of 9 affected animals. Among 14 other isolated strictly anaerobic microorganisms belonging to different species or genera only 4 strains showed a low degree of elastolysis. The 14 antimicrobial agents studied effectively inhibited "in vitro" growth of B. nodosus.

A role for DNA characterisation in ovine footrot.

Bacteroides nodosus involved in several outbreaks of ovine footrot over a number of years were subjected to DNA restriction endonuclease analysis. Individual isolates were found to have characteristic Bam HI profiles which permitted their accurate identification and differentiation from other isolates. Bam HI profiles of B. nodosus isolates were used in epidemiological investigations involving consecutive outbreaks of footrot on individual and neighbouring farms. The relationship of given isolates to a common source could be established by this means. Restriction endonuclease analysis provides an additional epidemiological tool in ovine footrot investigations as it accurately identifies interstrain differences in a manner not possible by conventional bacteriological and serological means.

Onset and remission of ovine footrot.

Sheep exposed to uncontrolled outbreaks of footrot were observed on one farm for 3 successive years and on another for one year. Observations were made from mid-winter to early summer. In each outbreak about 70% or more of sheep exposed to footrot acquired the disease. Natural remission occurred in each outbreak and some cases healed while new cases continued to develop. A feature of all outbreaks observed was that a much higher proportion of late onset cases healed than cases which developed early in the outbreaks. By contrast, 90% of sheep already affected before spring had lesions which persisted into next summer. It is suggested that there is a spectrum of resistance to footrot among sheep. This spectrum includes animals which remain chronically infected and those that do not become infected at all. Intermediate levels of resistance are reflected firstly in the time taken by different groups of sheep, to become affected after exposure and secondly, to heal after becoming affected.

Quantitation by ELISA of pili and sheep antibodies to the pili of Bacteroides nodosus.

ELISA systems have been developed to quantitate the isotypic antibody response of sheep naturally infected with B. nodosus isolate 198 or injected with pili from isolate 198 in oil emulsion vaccines. The predominant humoral antibody detected following vaccination was IgG1, with substantially lower amounts of IgG2 and IgM. The antibody response was relatively specific for the pilus antigen from isolate 198. Although weak cross reactivities were detected with antiserums to some other isolates, ELISA IgG antibody titres in excess of 200 offer a tentative identification of the isolates of B. nodosus involved in natural outbreaks of footrot. A related ELISA was also developed to quantitate the amount of pili in cell suspensions and crude preparations of pili used in vaccines.