Image courtesy Mr. Ian Kracalik

Evaluating the Impact of Livestock Vaccination Policies on the Epidemiology of Human Zoonotic Diseases in the Former Soviet Union

Speaker: Ian Kracalik

PhD Student, Department of Geography, University of Florida

Thursday, January 26, 2017

3:00-3:50 PM (Period 8)

Turlington Hall Room 3012

University of Florida

All are welcome to attend.

Image courtesy PLoS Neglected Tropical Diseases
Image courtesy PLoS Neglected Tropical Diseases

KRACALIK, MORRIS, BLACKBURN – Cholera in Cameroon, 2000-2012: Spatial and Temporal Analysis at the Operational (Health District) and Sub Climate Levels

Moise C. Ngwa, Song Liang, Ian T. Kracalik, Lillian Morris, Jason K. Blackburn, Leonard M. Mbam, Simon Franky Baonga Ba Pouth, Andrew Teboh, Yang Yang, Mouhaman Arabi, Jonathan D. Sugimoto, John Glenn Morris Jr.

Article first published online: 17 NOV 2016 PLoS Neglected Tropical Diseases

DOI: 10.1371/journal.pntd.0005105


Cholera was first reported in Cameroon in 1971. From 2000–2012, Cameroon reported on average 3,344.2 cases per year. When we divided the country into its four climate subzones (Sudano-Sahelian, Tropical Humid, Guinea Equatorial, and Equatorial Monsoon), there were very different patterns of spatial clustering of health districts with elevated attack rates, as well as differing sets of ecological determinants of cases counts. In the northern Sudano-Sahelian climate subzone, reported cases tended to occur between July and September, during the rainy season; whereas, the southern Equatorial Monsoon subzone reported cases year-round, with the lowest burden during the same rainy season. As cholera displays different epidemiological patterns by subzone, a single approach to controlling cholera for the whole nation does not appear to be viable. Additional prospective epidemiological studies are needed to further elucidate subzone-specific determinants of cholera burden, in order to provide sufficient evidence-based guidance for the formulation and assessment of regionally tailored intervention strategies.

Read the full publication at PLoS Neglected Tropical Diseases


State of Origin: California

Degree Program: PhD

Entered Program: Fall 2015

Expected Graduation: Spring 2017

Dissertation Topic: TBD

Areas of interest: Medical geography, epidemiology, public health policy, and spatial analysis

Adviser: Dr. Jason Blackburn

Educational Background

  • B.A. in Geogeraphy, California State University, Humboldt
  • M.A. in Geography, University of Florida
  • M.P.H.. in Epidemiology, University of Florida

BLACKBURN, KRACALIK – Applying Science: opportunities to inform disease management policy with cooperative research within a One Health framework

Jason K. Blackburn, Ian T. Kracalik and Jeanne M. Fair

Article first published online: 07 December 2015 Frontiers in Public Health

DOI: 10.3389/fpubh.2015.00276

ABSTRACT: The ongoing Ebola outbreak in West Africa and the current saiga antelope die off in Kazakhstan each represent very real and difficult to manage public or veterinary health crises. They also illustrate the importance of stable and funded surveillance and sound policy for intervention or disease control. While these two events highlight extreme cases of infectious disease (Ebola) or (possible) environmental exposure (saiga), diseases such as anthrax, brucellosis, tularemia, and plague are all zoonoses that pose risks and present surveillance challenges at the wildlife-livestock-human interfaces. These four diseases are also considered important actors in the threat of biological terror activities and have a long history as legacy biowarfare pathogens. This paper reviews recent studies done cooperatively between American and institutions within nations of the Former Soviet Union (FSU) focused on spatiotemporal, epidemiological, and ecological patterns of these four zoonoses. We examine recent studies and discuss the possible ways in which techniques, including ecological niche modeling, disease risk modeling, and spatio-temporal cluster analysis, can inform disease surveillance, control efforts and impact policy. Our focus is to posit ways to apply science to disease management policy and actual management or mitigation practices. Across these examples, we illustrate the value of cooperative studies that bring together modern geospatial and epidemiological analyses to improve our understanding of the distribution of pathogens and diseases in livestock, wildlife, and humans. For example, ecological niche modeling can provide national level maps of pathogen distributions for surveillance planning, while space-time models can identify the timing and location of significant outbreak events for defining active control strategies. We advocate for the need to bring the results and the researchers from cooperative studies into the meeting rooms where policy is negotiated and use these results to inform future disease surveillance and control or eradication campaigns.

Read the full publication at Frontiers in Public Health

KRACALIK, BLACKBURN – Human Anthrax Transmission at the Urban–Rural Interface, Georgia

Ian Kracalik, Lile Malania, Paata Imnadze and Jason K. Blackburn

Article first published online: 5 OCT 2015 The American Journal of Tropical Medicine and Hygiene

DOI: 10.4269/ajtmh.15-0242

ABSTRACT: Human anthrax has increased dramatically in Georgia and was recently linked to the sale of meat in an urban market. We assessed epidemiological trends and risk factors for human anthrax at the urban–rural interface. We reviewed epidemiologic records (2000–2012) that included the place of residence (classified as urban, peri-urban, or rural), age, gender, and self-reported source of infection (handling or processing animal by-products and slaughtering or butchering livestock). To estimate risk, we used a negative binomial regression. The average incidence per 1 million population in peri-urban areas (24.5 cases) was > 2-fold higher compared with rural areas and > 3-fold higher compared with urban area. Risk from handling or purchasing meat was nearly 2-fold higher in urban areas and > 4-fold higher in peri-urban areas compared with rural area. Our findings suggest a high risk of anthrax in urban and peri-urban areas likely as a result of spillover from contaminated meat and animal by-products. Consumers should be warned to purchase meat only from licensed merchants.

Read the full publication at The American Journal of Tropical Medicine and Hygiene

KRACALIK, BLACKBURN – Environmental Monitoring and Surveillance of Rodents and Vectors for Francisella tularensis Following Outbreaks of Human Tularemia in Georgia

Elashvili Eka, Kracalik Ian, Burjanadze Irma, Datukishvili Sophio, Chanturia Gvantsa, Tsertsvadze Nikoloz, Beridze Levan, Shavishvili Merab, Dzneladze Archil, Grdzelidze Marina, Imnadze Paata, Pearson Andrew, and Blackburn Jason K

Article first published online: 30 September 2015 Vector-Borne and Zoonotic Diseases

DOI: 10.1089/vbz.2015.1781

ABSTRACT: Tularemia is a re-emerging bacterial zoonosis, broadly distributed across the northern hemisphere. In Georgia, there is a history of human tularemia outbreaks dating back to the 1940s. In response to outbreaks, health officials initiated long-term field surveillance and environmental monitoring. The objective of our study was to obtain information from 57 years of field surveys to identify species that play a role in the occurrence Francisella tularensis subsp. holarctica in the environment in Georgia. We collected historical data on human outbreaks, field collections, population dynamics of the common vole (Microtus arvalis), and conducted surveys on small mammals and vectors from five regions in Georgia during 1956–2012. Bacterial isolation was conducted using standard culturing techniques, and isolation rates for species were obtained for a subset of years. We used a Spearman rank correlation to test for associations between the density of the common vole and isolation rates. From 1956 through 2012, there were four recorded outbreaks of human tularemia (362 cases). A total of 465 bacterial isolates of F. tularensis subsp. holarctica were obtained from 27 species and environmental samples. The number of isolations was highest in the common vole (M. arvalis; 149 isolates; 32%) and Dermacentor marginatus ticks (132 isolates; 28%); isolation rates ranged between 0–0.91% and 0–0.47%, respectively. Population dynamics of the common vole were not correlated with the isolation rate. Given the history of tularemia re-emergence in Georgia, continued field surveys and environmental monitoring may provide an early indication of outbreak risk in humans. In conclusion, our findings provide evidence of long-standing foci of F. tularensis subsp. holarctica that are likely maintained by the common vole–tick cycle.

Read the full publication at Vector-Borne and Zoonotic Diseases

BARRO, KRACALIK, BLACKBURN – study compared three local cluster detection methods to identify local hotspots of human cutaneous anthrax transmission in the country of Georgia where cases have been steadily

Alassane S. Barro, Ian T. Kracalik, Lile Malania, Nikoloz Tsertsvadze,
Julietta Manvelyan, Paata Imnadze, Jason K. Blackburn

ABSTRACT: This study compared three local cluster detection methods to identify local hotspots of human cutaneous anthrax (HCA) transmission in the country of Georgia where cases have been steadily increasing since the dissolution of the Soviet Union. Recent reports have indicated that the disease has reached historical levels in 2012 highlighting the need for better informed policy recommendations and targeted control measures. The purpose of this paper was to identify spatial clusters of HCA to aid in the implementation of targeted public health interventions. At the same time, we compared the utility of different statistical tests in identifying hotspots. We used the Getis-Ord ðG*i ðdÞÞ, a multidirectional optimal ecotope-based algorithm (AMOEBA) e a cluster morphology statistic, and the spatial scan statistic in SaTScan™. Data on HCA cases from 2000 to 2012 at the community level were aggregated to an 8 8 km grid surface and population data from the Global Rural and Urban Mapping Project (GRUMP) were used to calculate local incidence. In general, there was agreement between tests in the locations of HCA hotspots. Significant local clusters of high HCA incidence were identified in the southern, eastern and western regions of Georgia. The G*i ðdÞ and spatial scan statistics appeared more sensitive but less specific than the AMOEBA algorithm. The scan statistic identified larger geographic areas as hotspots of transmission. In general, the spatial scan statistic and G*i ðdÞ performed well for spatial clusters with lower incidence rates, whereas AMOEBA was well suited for defining local spatial clusters of higher HCA incidence. In resource constrained areas, efficient allocation of public health interventions is crucial. Our findings identified hotspots
of HCA that can be used to target public health interventions such as livestock vaccination and
training on proper outbreak management. This paper illustrates the benefits of evaluating statistical
approaches for defining disease hotspots and highlights differences in these clustering approaches
applicable beyond public health studies.

© 2015 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND
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