Epidemiologic Questions from Anthrax Outbreak, Hunter Valley, Australia

Dürrheim, David N; Freeman, P.G.; Roth, Ian; Hornitzky, M.

doi:10.3201/eid1505.081744

Cited by 26 publications

(36 citation statements)

References 2 publications

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“…Soil characteristics that restrict spore dispersal may increase the likelihood of grazing animals acquiring a lethal dose (Hugh‐Jones & Blackburn 2009), as may drainage channels that concentrate spores. ‘Incubator areas’ have been hypothesized to occur when favourable soils collect water and organic matter providing a milieu for spore germination and multiplication (Durrheim et al. 2009).…”

Section: Discussionmentioning

confidence: 99%

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Predictability of anthrax infection in the Serengeti, Tanzania

Hampson

Lembo

Bessell

et al. 2011

Journal of Applied Ecology

109

129

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Summary1. Anthrax is endemic throughout Africa, causing considerable livestock and wildlife losses and severe, sometimes fatal, infection in humans. Predicting the risk of infection is therefore important for public health, wildlife conservation and livestock economies. However, because of the intermittent and variable nature of anthrax outbreaks, associated environmental and climatic conditions, and diversity of species affected, the ecology of this multihost pathogen is poorly understood. 2. We explored records of anthrax from the Serengeti ecosystem in north-west Tanzania where the disease has been documented in humans, domestic animals and a range of wildlife. Using spatial and temporal case-detection and seroprevalence data from wild and domestic animals, we investigated spatial, environmental, climatic and species-specific associations in exposure and disease. 3. Anthrax was detected annually in numerous species, but large outbreaks were spatially localized, mostly affecting a few focal herbivores. 4. Soil alkalinity and cumulative weather extremes were identified as useful spatial and temporal predictors of exposure and infection risk, and for triggering the onset of large outbreaks. 5. Interacting ecological and behavioural factors, specifically functional groups and spatiotemporal overlap, helped to explain the variable patterns of infection and exposure among species. 6. Synthesis and applications. Our results shed light on ecological drivers of anthrax infection and suggest that soil alkalinity and prolonged droughts or rains are useful predictors of disease occurrence that could guide risk-based surveillance. These insights should inform strategies for managing anthrax including prophylactic livestock vaccination, timing of public health warnings and antibiotic provision in high-risk areas. However, this research highlights the need for greater surveillance (environmental, serological and case-detection-orientated) to determine the mechanisms underlying anthrax dynamics.

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Section: Discussionmentioning

confidence: 99%

“…Elsewhere, outbreaks have been associated with heavy rains (Lindeque & Turnbull 1994; Mlengeya et al. 1998; Wafula, Patrick & Charles 2008; Bellan 2010), which are hypothesized to unearth spores and amplify vector populations (Durrheim et al. 2009; Hugh‐Jones & Blackburn 2009; Lewerin et al.…”

Section: Introductionmentioning

confidence: 99%

Predictability of anthrax infection in the Serengeti, Tanzania

Hampson

Lembo

Bessell

et al. 2011

Journal of Applied Ecology

109

129

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“…The timing of anthrax outbreaks within a particular locality tend to have a seasonal signal, although the season during which most cases occur varies from locality to locality. Outbreaks consisting primarily of grazing wildlife or livestock occur in seasonal or weather conditions along a spectrum from drought (Fox et al 1977, Shiferaw et al 2002, Muoria et al 2007, Wafula et al 2008, Hampson et al 2011, to hot dry seasons often following years of unusually high rainfall (Rees et al 1977, Gates et al 1995, Dragon et al 1999, Turner et al 1999, Himsworth and Argue 2008, Chikerema et al 2012, to transition periods between dry-wet or wet-dry conditions (Fox et al 1973, Parkinson et al 2003, Siamudaala et al 2006, Mongoh et al 2008, to wet season outbreaks (Lindeque and Turnbull 1994, Durrheim et al 2009, Chikerema et al 2012. Some authors do not specify the time scale in which the described weather patterns occur in relation to the outbreak.…”

Section: Introductionmentioning

confidence: 99%

“…Anthrax outbreaks occur world-wide and are of concern for animal conservation (Leendertz et al 2004, Muoria et al 2007), wildlife management (Clegg et al 2007, Wafula et al 2008, agriculture (Mongoh et al 2008, Durrheim et al 2009, Lewerin et al 2010) and public health (Siamudaala et al 2006). Anthrax is caused by the bacterium Bacillus anthracis which can infect a wide range of animal species, but mortalities are most commonly observed in herbivorous mammals.…”

Section: Introductionmentioning

confidence: 99%

Soil ingestion, nutrition and the seasonality of anthrax in herbivores of Etosha National Park

et al. 2013

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Abstract. Anthrax, caused by the bacterium Bacillus anthracis, is a seasonally occurring infectious disease affecting primarily herbivorous wildlife and livestock. The seasonality of anthrax outbreaks varies among locations, making it difficult to develop a single consistent ecological description of this disease. Over 44 years of mortality surveillance, most anthrax cases in Etosha National Park, Namibia are observed in the wet season, although elephants have an anthrax mortality peak in the dry season. Focusing on three host species (plains zebra, Equus quagga; African elephant, Loxodonta africana; and springbok, Antidorcas marsupialis) occupying the endemic anthrax area of Etosha National Park, Namibia, we tested two commonly posited causes of anthrax seasonality in herbivores: increased pathogen exposure due to greater soil contact, and increased host susceptibility due to seasonal nutritional stress. These hypotheses were assessed using fecal sampling and measurement of the percentage of fecal silicates as an index of soil ingestion and fecal nitrogen, phosphorus and crude fiber as nutritional indices. Nutritional quality for all three species was higher in wet than dry seasons. Comparing among wet seasons, nutritional indices showed either a decline in nutrition with increasing rainfall or no significant pattern. All three species had greater soil ingestion in the wet season than the dry season. Higher soil contact during the anthrax peak suggests that anthrax seasonality may in part be due to heightened exposure to B. anthracis in wet seasons, for zebra and springbok. Elephant anthrax deaths do not correspond with the season of increased soil ingestion or grazing, suggesting that other behavioral mechanisms may overshadow foraging-based risk factors for this species. Nutritional stress is unlikely the primary causative factor in wet season anthrax systems, although nutritional stress sufficient to reduce resistance is difficult to assess non-invasively in wild herbivores. In contrast, increased soil ingestion may be an important predisposing factor for wet season anthrax outbreaks. Ultimately, the amount of soil ingested and its importance in the transmission of soil-borne pathogens will vary based on foraging behaviors, intake rates, grassland structure and on the likelihood that foraging areas intersect with pathogen aggregations in the environment.

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“…Although the disease is found in almost all countries, it is mostlyprevalent in tropical and sub-tropical countries (Biswas et al, 2011). In recent years, the disease has been reported in Sweden (Lewerin et al, 2010), Italy (Fasanella et al, 2010), USA , Australia (Durrheim et al, 2009), and some other countries in Europe. B. anthracis forms spore in unfavorable conditions, which is resistant to heat and chemical disinfectants, and this may persist in soil as viable for several decades (Hirsh and Zee, 1999;Dragon et al, 2001;OIE, 2004).…”

Section: Introductionmentioning

confidence: 99%

ELISA Based Anthrax Antibody Titer in Cattle Induced by Locally Prepared Anthrax Vaccine Originated from Sterne F-24 Strain in Bangladesh

et al. 2016

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Vaccination is usually practiced to prevent and control anthrax in Bangladesh. For this purpose, vaccine prepared from Sterne F-24 strain ofBacillus anthracisby Livestock Research Institute (LRI), Mohakhali, Dhakahas long been used in this country. However, in some cases anthrax occurred in vaccinated animals in Bangladesh. A total of 100 cattle at LalTeer Livestock Research and Development Farm, LalTeerLivestock Limited, Bangladesh, aging between 3-6 years and weighing between 250-400 kg were randomly selected for vaccination purpose. Blood samples (n=100) were collected before the vaccination for collecting pre-vaccination serum, andthe animals were vaccinated (at 1 mL/animal; 1x10 7 spores/mL) with the anthrax vaccine produced by LRI. All blood samples from the vaccinated animals were collected on day 7, 28, 60, 90, 120, 150, 180, 240, 270, 300, 330, and 360 of post-vaccination, and serum samples were prepared. The antibody levels in the serum samples against anthrax were monitored using an Enzyme-Linked Immunosorbent Assay (ELISA). Over the course of 12 months, the antibody titers were found at the level higher than the reference value. Though there were reports on anthrax suspected cases in this farm, no such cases were reported during the study period. Thus, the vaccine appears to induce adequate antibody response against anthrax in Bangladesh.

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Epidemiologic Questions from Anthrax Outbreak, Hunter Valley, Australia

Cited by 26 publications

References 2 publications

Predictability of anthrax infection in the Serengeti, Tanzania

Predictability of anthrax infection in the Serengeti, Tanzania

Soil ingestion, nutrition and the seasonality of anthrax in herbivores of Etosha National Park

ELISA Based Anthrax Antibody Titer in Cattle Induced by Locally Prepared Anthrax Vaccine Originated from Sterne F-24 Strain in Bangladesh

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