Until recently, most studies on the role of hormones in plant-pathogen interactions focused on salicylic acid (SA), jasmonic acid (JA), and ethylene (ET). It is now clear that pathogen-induced modulation of signaling via other hormones contributes to virulence. A picture is emerging of complex crosstalk and induced hormonal changes that modulate disease and resistance, with outcomes dependent on pathogen lifestyles and the genetic constitution of the host. Recent progress has revealed intriguing similarities between hormone signaling mechanisms, with gene induction responses often achieved by derepression. Here, we report on recent advances, updating current knowledge on classical defense hormones SA, JA, and ET, and the roles of auxin, abscisic acid (ABA), cytokinins (CKs), and brassinosteroids in molding plant-pathogen interactions. We highlight an emerging theme that positive and negative regulators of these disparate hormone signaling pathways are crucial regulatory targets of hormonal crosstalk in disease and defense.

Hormone Crosstalk in Plant Disease and Defense: More Than Just JASMONATE-SALICYLATE Antagonism

Many ``real-world'' networks are clearly defined while most ``social'' networks are to some extent subjective. Indeed, the accuracy of empirically-determined social networks is a question of some concern because individuals may have distinct perceptions of what constitutes a social link. One unambiguous type of connection is sexual contact. Here we analyze data on the sexual behavior of a random sample of individuals, and find that the cumulative distributions of the number of sexual partners during the twelve months prior to the survey decays as a power law with similar exponents $\alpha \approx 2.4$ for females and males. The scale-free nature of the web of human sexual contacts suggests that strategic interventions aimed at preventing the spread of sexually-transmitted diseases may be the most efficient approach.

The Web of Human Sexual Contacts

Hormone balance and abiotic stress tolerance in crop plants

Tick-borne rickettsioses are caused by obligate intracellular bacteria belonging to the spotted fever group of the genus Rickettsia. These zoonoses are among the oldest known vector-borne diseases. However, in the past 25 years, the scope and importance of the recognized tick-associated rickettsial pathogens have increased dramatically, making this complex of diseases an ideal paradigm for the understanding of emerging and reemerging infections. Several species of tick-borne rickettsiae that were considered nonpathogenic for decades are now associated with human infections, and novel Rickettsia species of undetermined pathogenicity continue to be detected in or isolated from ticks around the world. This remarkable expansion of information has been driven largely by the use of molecular techniques that have facilitated the identification of novel and previously recognized rickettsiae in ticks. New approaches, such as swabbing of eschars to obtain material to be tested by PCR, have emerged in recent years and have played a role in describing emerging tick-borne rickettsioses. Here, we present the current knowledge on tick-borne rickettsiae and rickettsioses using a geographic approach toward the epidemiology of these diseases.

Update on Tick-Borne Rickettsioses around the World: a Geographic Approach

During most of the 20th century, the epidemiology of tick-borne rickettsioses could be summarized as the occurrence of a single pathogenic rickettsia on each continent. An element of this paradigm suggested that the many other characterized and noncharacterized rickettsiae isolated from ticks were not pathogenic to humans. In this context, it was considered that relatively few tick-borne rickettsiae caused human disease. This concept was modified extensively from 1984 through 2005 by the identification of at least 11 additional rickettsial species or subspecies that cause tick-borne rickettsioses around the world. Of these agents, seven were initially isolated from ticks, often years or decades before a definitive association with human disease was established. We present here the tick-borne rickettsioses described through 2005 and focus on the epidemiological circumstances that have played a role in the emergence of the newly recognized diseases.

Tick-Borne Rickettsioses around the World: Emerging Diseases Challenging Old Concepts

Serum samples were collected from 582 horses from 40 stud farms in the State of Sao Paulo and tick (Acari: Ixodidae) infestations were evaluated on them Serum samples were subjected to the complement fixation test (CFT) and a competitive inhibition ELISA (cELISA) for Babesia caballi and Theileria equi Logistic regression analyses were performed to construct multivariate models that could explain the dependent variable (horses positive for B caballi or T equi) as a function of the independent variables (presence or abundance of each one of the tick species found on the farms) A higher overall prevalence of B caballi (541%) than of T equi (216%) was found by the two tests The ticks Dermacentor nitens Neumann, 1897, Amblyomma cajennense (Fabricius, 1787) and Rhipicephalus (Boophilus) microplus (Canestrini, 1887) were present on horses on 38 (95%), 20 (50%), and 4 (10%) farms, respectively Infestations by D nitens were statistically associated with B caballi-positive horses on the farms by either the CFT or cELISA Infestations by A cajennense were statistically associated with T equi-positive horses on the farms by either CFT or cELISA

Prevalence of equine Piroplasmosis and its association with tick infestation in the State of São Paulo, Brazil Prevalência da Piroplasmose equina e sua associação com infestação por carrapatos no Estado de São Paulo

Economic analysis of bovine brucellosis control in the Rondônia state, Brazil

Glanders is an anthropozoonosis caused by the bacteria Burkholderia mallei, affecting mainly equids. It has been eradicated in North America, Australia, and Western Europe, but continues to occur sporadically in countries in Asia, Africa, the Middle East, and South America. Its notification is mandatory by the World Organization for Animal Health. After 30 years, the disease reappeared in Brazil in 1999 and, thereafter, 1,413 outbreaks have been reported. However, the epidemiological situation of the disease in the country is not adequately known. Thus, 2718 animals from 654 properties in the state of Pará were randomly selected by sampling and examined using a serial protocol with Complement Fixation and Western Blot serological tests. The prevalence of properties infected with glanders in the state was estimated at 1.68% [0.84; 3.33] and of seropositive animals at 0.50% [0.27; 0.94]. The introduction of animals was individualized as a risk factor for disease introduction in the properties (OR = 5.9 [1.4; 25.5]). Despite the low prevalence of infected properties and seropositive animals, the state must review actions to fight the disease, considering that the strategies implemented have not affected the endemic balance of the disease. This process must involve all public and private agents interested in the topic.

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Epidemiological Situation of Glanders in the State of Pará, Brazil


 Foot-and-mouth disease (FMD) outbreaks in cloven-hoofed animals cause substantial economic impacts because of animal depopulation, increased government spending on control, eradication and surveillance measures, and bans on international trade. This study employs a computable general equilibrium (CGE) modeling framework in tandem with results from an epidemiological model to evaluate the economic consequences of a hypothetical FMD outbreak in Brazil. FMD-induced productivity losses and restrictions on international trade of livestock and meat products are applied as exogenous shocks in the economic model. Results show increased bilateral trade of beef and pork, mainly in South America, North Africa, and Russia. Simulated welfare losses in Brazil range from ${\$}$132 million to ${\$}$271 million depending on the severity of trade restrictions imposed. This study expands the rich literature on animal health economics. Results highlight the importance of maintaining the health of Brazilian herds, especially when considering Brazil's position as one of the main meat suppliers in the international market.

Economic assessment of foot-and-mouth disease outbreaks in Brazil

Bovine tuberculosis (bTB) impacts considerably animal production and one health worldwide. To describe the prevalence, risk factors, and spatial pattern of the disease in the state of Paraná, Brazil, a cross-sectional study was conducted from September 2018 to February 2019. The area was divided into seven regions. Within each region, farms were randomly selected, and a predetermined number of cows was selected and tested by a comparative cervical tuberculin test. 17,210 animals were tested across 1757 farms. Herd prevalence of bTB-infected herds in Paraná was 2.5% [1.87-3.00%]. It has varied from 0.8 to 3.98% among seven regions, with clustering being detected in the west, central, and northeast areas. Animal prevalence was 0.35% [0.21-0.59%] and has varied from 0.08 to 0.6% among the pre-set regions. No major shifts in the prevalence of bTB were detected since 2007. Large-sized herds, dairy production, and feeding with whey were detected to be correlated with the presence of bTB. Exclusively among dairy herds, veterinary assistance from cooperatives, possession of self-owned equipment to cool milk, and feeding with whey were correlated with the disease. Considering these results, it is recommended that the state of Paraná seek to implement a surveillance system for the detection of bTB-infected herds transforming them into free ones, if possible, incorporating elements of risk-based surveillance. Health education is also recommended to inform farmers about the risks of introducing animals without testing and of feeding raw whey to calves. 

/pdf/apparent-prevalence-and-risk-factors-for-bovine-tuberculosis-3scw6vlw.pdf

Apparent prevalence and risk factors for bovine tuberculosis in the state of Paraná, Brazil: an assessment after 18 years since the beginning of the Brazilian program

Fernando Ferreira

Papers

Prevalence of equine Piroplasmosis and its association with tick infestation in the State of São Paulo, Brazil Prevalência da Piroplasmose equina e sua associação com infestação por carrapatos no Estado de São Paulo

Economic analysis of bovine brucellosis control in the Rondônia state, Brazil

Epidemiological Situation of Glanders in the State of Pará, Brazil

Economic assessment of foot-and-mouth disease outbreaks in Brazil

Apparent prevalence and risk factors for bovine tuberculosis in the state of Paraná, Brazil: an assessment after 18 years since the beginning of the Brazilian program