Human tularaemia associated with exposure to domestic dogs-United States, 2006-2016

Pediatric Oropharyngeal Tularemia Cases: Challenges in Management

Background: Tularemia is one of the most prevalent zoonoses across the world. Patients in Turkiye mostly contract the oropharyngeal form, acquired through drinking, or contact with microorganism-contaminated water. Methods: Patients with oropharyngeal tularemia aged under 18 years and diagnosed between January 01, 2017, and December 31, 2020, were evaluated retrospectively. Tularemia was diagnosed in patients with compatible histories, symptoms, clinical presentations, and laboratory test results. Results: The mean age of 38 children was 12.1 ± 3.4 years, and the female/male ratio was 0.58 (14/24). The mean duration of symptoms on admission was 33.8 ± 26.2 days. All children had enlarged lymph nodes. Malaise, fever, and loss of appetite were other frequent symptoms. Patients were treated with antibiotics for a mean of 26.2 ± 18.8 days. Gentamycin was the most frequently used antibiotic (either alone or in combination) (n = 29, 76.3%). Twenty-six (68.4%) patients underwent surgical procedures in addition to antibiotherapy. Five (13.2%) required secondary total excision. Patients with higher leukocyte counts at admission received a combination of antibiotherapy plus surgery, rather than antibiotics alone. No relapses, reretreatment requirement, or mortality were observed after 12 months of follow-up. Conclusions: Oropharyngeal tularemia in children can require longer courses of antibiotic treatment with more than one drug and more frequent surgery than previously suggested in the literature, especially if the patients are admitted late to the hospital, symptom duration is prolonged, and appropriate treatment is initiated late. Higher leukocyte counts on admission may be prognostic for longer antibiotic treatment course and suppurative complications that require surgery. Raising awareness among patients and physicians is essential.

Tularemia From Veterinary Occupational Exposure

Tularemia is a disease caused by Francisella tularensis, a highly infectious bacteria that can be transmitted to humans by direct contact with infected animals. Because of the potential for zoonotic transmission of F. tularensis, veterinary occupational risk is a concern. Here, we report on a human case of tularemia in a veterinarian after an accidental needlestick injury during abscess drainage in a sick dog. The veterinarian developed ulceroglandular tularemia requiring hospitalization but fully recovered after abscess drainage and a course of effective antibiotics. To systematically assess veterinary occupational transmission risk of F. tularensis, we conducted a survey of veterinary clinical staff after occupational exposure to animals with confirmed tularemia. We defined a high-risk exposure as direct contact to the infected animal's body fluids or potential aerosol inhalation without use of standard personal protective equipment (PPE). Survey data included information on 20 veterinary occupational exposures to animals with F. tularensis in 4 states. Veterinarians were the clinical staff most often exposed (40%), followed by veterinarian technicians and assistants (30% and 20%, respectively). Exposures to infected cats were most common (80%). Standard PPE was not used during 80% of exposures; a total of 7 exposures were categorized as high risk. Transmission of F. tularensis in the veterinary clinical setting is possible but overall risk is likely low. Veterinary clinical staff should use standard PPE and employ environmental precautions when handling sick animals to minimize risk of tularemia and other zoonotic infections; postexposure prophylaxis should be considered after high-risk exposures to animals with suspected or confirmed F. tularensis infection to prevent tularemia.

Tularemia - a re-emerging disease with growing concern

Tularemia caused by Gram-negative, coccobacillus bacterium, Francisella tularensis, is a highly infectious zoonotic disease. Human cases have been reported mainly from the United States, Nordic countries like Sweden and Finland, and some European and Asian countries. Naturally, the disease occurs in several vertebrates, particularly lagomorphs. Type A (subspecies tularensis) is more virulent and causes disease mainly in North America; type B (subspecies holarctica) is widespread, while subspecies mediasiatica is present in central Asia. F. tularensis is a possible bioweapon due to its lethality, low infectious dosage, and aerosol transmission. Small mammals like rabbits, hares, and muskrats are primary sources of human infections, but true reservoir of F. tularensis is unknown. Vector-borne tularemia primarily involves ticks and mosquitoes. The bacterial subspecies involved and mode of transmission determine the clinical picture. Early signs are flu-like illnesses that may evolve into different clinical forms of tularemia that may or may not include lymphadenopathy. Ulcero-glandular and glandular forms are acquired by arthropod bite or handling of infected animals, oculo-glandular form as a result of conjunctival infection, and oro-pharyngeal form by intake of contaminated food or water. Pulmonary form appears after inhalation of bacteria. Typhoidal form may occur after infection via different routes. Human-to-human transmission has not been known. Diagnosis can be achieved by serology, bacterial culture, and molecular methods. Treatment for tularemia typically entails use of quinolones, tetracyclines, or aminoglycosides. Preventive measures are necessary to avoid infection although difficult to implement. Research is underway for the development of effective live attenuated and subunit vaccines.

Tracking the footsteps of Francisella tularensis: Bacteriological and serological monitoring in epidemic areas in Ankara

The study aimed to detect Francisella tularensis (F. tularensis) in water samples and to investigate the seroreactivity of sheep to tularemia in endemic areas where human tularemia cases have been reported in Ankara, Turkey. For the isolation of F. tularensis, 50 water samples were collected from rural areas of 5 regions of Ankara (Turkey) and selectively cultured on Francis medium supplemented with 8-9 % sheep blood and antibiotics (100 IU/ml penicillin G, 100 mg/L cycloheximide, 80,000 U/L polymixin B). No F. tularensis isolate was cultivated from the water samples. To determine the seroreactivity of sheep to tularemia, 1006 sheep blood samples were collected from the regions, where human tularemia is endemic. A microagglutination test (MAT) identified significant antibody titers, ranging from 1/20-1/640 in 181 (17.99 %) of the investigated sheep sera. Further investigation is required in order to evaluate and confirm a possible epidemiologic relationship between human outbreaks and probable role of sheep or other sources.

Ulceroglandular form of tularemia after squirrel bite: a case report

Background

The diagnosis of tularemia is not often considered in Germany as the disease is still rare in this country. Nonetheless, Francisella tularensis, the causative agent of tularemia, can infect numerous animal species and should, therefore, not be neglected as a dangerous pathogen. Tularemia can lead to massively swollen lymph nodes and might even be fatal without antibiotic treatment. To our knowledge, the case described here is the first report of the disease caused by a squirrel bite in Germany.

Case presentation

A 59-year-old German woman with a past medical history of hypothyroidism and cutaneous lupus erythematosus presented at the emergency room at St. Katharinen Hospital with ongoing symptoms and a swollen right elbow persisting despite antibiotic therapy with cefuroxime for 7 days after she had been bitten (right hand) by a wild squirrel (Eurasian red squirrel). After another 7 days of therapy with piperacillin/tazobactam, laboratory analysis using real-time polymerase chain reaction (PCR) confirmed the suspected diagnosis of tularemia on day 14. After starting the recommended antibiotic treatment with ciprofloxacin, the patient recovered rapidly.

Conclusion

This is the first report of a case of tularemia caused by a squirrel bite in Germany. A naturally infected squirrel has recently been reported in Switzerland for the first time. The number of human cases of tularemia has been increasing over the last years and, therefore, tularemia should be taken into consideration as a diagnosis, especially in a patient bitten by an animal who also presents with headache, increasing pain, lymphadenitis, and fever, as well as impaired wound healing. The pathogen can easily be identified by a specific real-time PCR assay of wound swabs and/or by antibody detection, for example by enzyme-linked immunosorbent assay (ELISA), if the incident dates back longer than 2 weeks.

Tularemia Proximal Interphalangeal Joint Septic Arthritis: A Case Report

CASE

A case of Francisella tularensis finger proximal interphalangeal joint septic arthritis secondary to feral cat bite is presented. The patient underwent operative debridement on presentation. On postoperative day 5, a gram-negative rod resembling F. tularensis was identified. The patient received 4 weeks of gentamicin for culture-confirmed ulceroglandular tularemia. At the final follow-up, the infection had resolved, and full function of the digit had been regained.

CONCLUSION

Francisella tularensis septic arthritis secondary to a feral cat bite is exceedingly rare but should be considered in the appropriate clinical context. Proper identification and treatment with antibiotics is essential for a positive outcome.

Assessment of Zoonotic Risk following Diagnosis of Canine Tularemia in a Veterinary Medical Teaching Hospital

Tularemia is a rare zoonotic disease found worldwide. The agent responsible for disease, Francisella tularensis, is one of the most highly infectious pathogens known, one that is capable of causing life-threatening illness with inhalation of <50 organisms. High infectivity explains concerns of its use in bioterrorism. This case describes a 4-year-old male neutered Australian shepherd presented for evaluation of hyporexia and fever. Physical examination revealed marked enlargement of the right superficial cervical lymph node. Tularemia lymphadenitis was diagnosed by lymph node aspiration cytology and culture. Public health officials were advised of the isolation of this zoonotic pathogen, and contact tracing was instituted. Seven individuals associated with the aspiration event were screened for tularemia and treated with prophylactic ciprofloxacin. All were negative, and none became sick. The dog was treated with doxycycline for 3 weeks, and clinical signs and physical examination abnormalities were resolved fully. The owner, a solid organ transplant recipient, was also screened for disease and received prophylactic doxycycline due to a history of shared exposure. The owner remained well throughout the course of his dog’s disease and has heightened awareness of potential zoonoses. This case highlights the importance of animals as a sentinel for human health threats and for coordination of human and veterinary care.

Epidemiological investigation of a tularaemia outbreak after a hare hunt in Bavaria, Germany, 2018

In November 2018, a tularaemia outbreak occurred in Bavaria, Germany, among participants of a hare hunt and butchery employees handling the hares. We conducted an epidemiological outbreak investigation, including a retrospective cohort study among hunting participants, to identify likely transmission routes and activities associated with infection. Twelve of 41 participants were antibody-positive for Francisella (F.) tularensis (attack rate: 29%). Cases reported influenza-like symptoms (n = 11), lymphadenopathy (n = 1) and conjunctivitis (n = 1). Infection only occurred in those hunting participants present while hares were processed, while risk of infection was highest when directly involved (RR = 10.0; 95%CI: 2.6-392). F. tularensis was isolated from 1/4 hares. Only two individuals reported using some of the recommended personal protective equipment (PPE). Occurrence of mainly non-specific symptoms, likely due to early treatment, was not indicative of a specific transmission route. Transmissions via direct (skin/mucosa) contact and by inhalation of contaminated aerosols seem plausible. Promoting and increasing appropriate use of PPE among people processing hares is crucial to prevent future outbreaks.

Hunting Dogs

Herding and hunting dogs are intense, high-drive dogs that work, and often live, outdoors and in constant or repeated close contact with domestic and wild animals. These dogs are at increased risk for injury and exposure to infectious diseases, toxic substances, and environmental threats. The common practice of feeding or allowing access to raw meat from farm or game animals enhances disease transmission risk. These dogs can be affected by infectious diseases and injurious agents that are rarely encountered in other groups of dogs. In addition, their extreme work ethic may lead to delays in diagnosis.

Francisella tularensis survey among ranchers and livestock in western Iran

Tularemia is a zoonotic disease that transmitted to humans and domestic animals by wildlife, especially rodents. There are some evidences of the circulation of F. tularensis in rodents, livestock, human populations, and surface waters in western parts of Iran. In this study, we investigated the exposure of livestock and ranchers to F. tularensis in the endemic regions of western Iran. Blood samples were collected from 289 sheep, 103 cattle, and 51 ranchers in 2018. Animal sera were tested by standard tube agglutination method. The specific IgGs against F. tularensis were evaluated by ELISA in human sera. Moreover, the extracted DNAs from 50 sheep spleen samples were evaluated using TaqMan real-time PCR for the presence of ISFtu2 and FopA genes. All animal sera and spleen samples were negative for tularemia. Of the 51 human samples, two samples were seropositive and one sample showed a borderline status for tularemia. Serologic evidence of F. tularensis in the ranchers but negative results in the livestock indicates different transmission routes in human populations and domestic animals in western Iran. Therefore, drinking contaminated water, contact to wildlife or rodents and arthropod bite should be considered as probable routes in the suspicious areas.

Outbreak of Tularemia in a Group of Hunters in Germany in 2018-Kinetics of Antibody and Cytokine Responses

In November 2018, an outbreak of tularemia occurred among hare hunters in Bavaria, Germany. At least one infected hare was confirmed as the source of infection. A number of hunting dogs showed elevated antibody titers to Francisella tularensis, but the absence of titer increases in subsequent samples did not point to acute infections in dogs. Altogether, 12 persons associated with this hare hunt could be diagnosed with acute tularemia by detection of specific antibodies. In nine patients, the antibody and cytokine responses could be monitored over time. Eight out of these nine patients had developed detectable antibodies three weeks after exposure; in one individual the antibody response was delayed. All patients showed an increase in various cytokines and chemokines with a peak for most mediators in the first week after exposure. Cytokine levels showed individual variations, with high and low responders. The kinetics of seroconversion has implications on serological diagnoses of tularemia.

Tularemia Goes West: Epidemiology of an Emerging Infection in Austria

The zoonotic disease tularemia is caused by the Gram-negative bacterium Francisella tularensis, with the two major subspecies tularensis and holarctica being responsible for infections in humans and animals. The F. tularensis subspecies holarctica is less virulent and prevalent in Europe and Asia. Over the last few centuries, few epidemic outbreaks and low numbers of infections have been registered in the eastern part of Austria, specifically in the provinces of Lower Austria, Burgenland, and Styria. The reported infections were mostly associated with hunting hares and the skinning of carcasses. Within the last decade, ticks have been identified as important vectors in Tyrol and served as first evidence for the spread of F. tularensis to Western Austria. In 2018, the pathogen was detected in hares in the provinces of Tyrol, Vorarlberg, and Salzburg. We presume that F. tularensis is now established in most regions of Austria, and that the investigation of potential host and vector animals should be spotlighted by public institutions. Tularemia in humans presents with various clinical manifestations. As glandular, ulceroglandular, and typhoidal forms occur in Austria, this infectious disease should be considered as a differential diagnosis of unknown fever.

Oculoglandular Tularemia From Crushing an Engorged Tick

We report on an unusual case of oculoglandular tularemia acquired after crushing a tick removed from a dog. As a droplet sprayed into the patient's eye the eyelids became inflamed, and on the fourth day, a high fever started. Prompt antibiotic treatment prevented serious complication.

Francisella tularensis infection in dogs: 88 cases (2014-2016)

OBJECTIVE

To characterize the epidemiology, clinical signs, and treatment of dogs with Francisella tularensis infection in New Mexico.

ANIMALS

87 dogs in which 88 cases of tularemia (1 dog had 2 distinct cases) were confirmed by the New Mexico Department of Health Scientific Laboratory Division from 2014 through 2016 and for which medical records were available.

PROCEDURES

Dogs were confirmed to have tularemia if they had a 4-fold or greater increase in anti-F tularensis antibody titer between acute and convalescent serum samples or F tularensis had been isolated from a clinical or necropsy specimen. Epidemiological, clinical, and treatment information were collected from the dogs' medical records and summarized.

RESULTS

All 88 cases of tularemia were confirmed by paired serologic titers; the first (acute) serologic test result was negative for 84 (95%) cases. The most common reported exposure to F tularensis was wild rodent or rabbit contact (53/88 [60%]). Dogs had a median number of 3 clinical signs at initial evaluation; lethargy (81/88 [92%]), pyrexia (80/88 [91%]), anorexia (67/88 [76%]), and lymphadenopathy (18/88 [20%]) were most common. For 32 (36%) cases, the dog was hospitalized; all hospitalized dogs survived.

CONCLUSIONS AND CLINICAL RELEVANCE

Dogs with F tularensis infection often had nonspecific clinical signs and developed moderate to severe illness, sometimes requiring hospitalization. Veterinarians examining dogs from tularemia-enzootic areas should be aware of the epidemiology and clinical signs of tularemia, inquire about potential exposures, and discuss prevention methods with owners, including reducing exposure to reservoir hosts and promptly seeking care for ill animals.

Tick-Borne Illness and Infective Endocarditis: A Rare Case of Tularemia

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Francisella tularensis infection, or tularemia, can cause infective endocarditis.

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Echocardiographic data are critical in prompt diagnosis of this rare clinical entity.

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Accurate diagnosis requires a high index of suspicion in the correct clinical context.

A Vaccinomics Approach for the Identification of Tick Protective Antigens for the Control of Ixodes ricinus and Dermacentor reticulatus Infestations in Companion Animals

Ticks and tick-borne pathogens affect health and welfare of companion animals worldwide, and some human tick-borne diseases are associated with exposure to domestic animals. Vaccines are the most environmentally friendly alternative to acaracides for the control of tick infestations, and to reduce the risk for tick-borne diseases affecting human and animal health. However, vaccines have not been developed or successfully implemented for most vector-borne diseases. The main limitation for the development of effective vaccines is the identification of protective antigens. To address this limitation, in this study we used an experimental approach combining vaccinomics based on transcriptomics and proteomics data with vaccination trials for the identification of tick protective antigens. The study was focused on Ixodes ricinus and Dermacentor reticulatus that infest humans, companion animals and other domestic and wild animals, and transmit disease-causing pathogens. Tick larvae and adult salivary glands were selected for analysis to target tick organs and developmental stages playing a key role during tick life cycle and pathogen infection and transmission. Two I. ricinus (heme lipoprotein and uncharacterized secreted protein) and five D. reticulatus (glypican-like protein, secreted protein involved in homophilic cell adhesion, sulfate/anion exchanger, signal peptidase complex subunit 3, and uncharacterized secreted protein) proteins were identified as the most effective protective antigens based on the criteria of vaccine E > 80%. The putative function of selected protective antigens, which are involved in different biological processes, resulted in vaccines affecting multiple tick developmental stages. These results suggested that the combination of some of these antigens might be considered to increase vaccine efficacy through antigen synergy for the control of tick infestations and potentially affecting pathogen infection and transmission. These antigens were proposed for commercial vaccine development for the control of tick infestations in companion animals, and potentially in other hosts for these tick species.

Ticks and Tularemia: Do We Know What We Don't Know?

Francisella tularensis, the causative agent of the zoonotic disease tularemia, is characterized by high morbidity and mortality rates in over 190 different mammalian species, including humans. Based on its low infectious dose, multiple routes of infection, and ability to induce rapid and lethal disease, F. tularensis has been recognized as a severe public health threat—being designated as a NIH Category A Priority Pathogen and a CDC Tier 1 Select Agent. Despite concerns over its use as a bioweapon, most U.S. tularemia cases are tick-mediated and ticks are believed to be the major environmental reservoir for F. tularensis in the U.S. The American dog tick (Dermacentor variabilis) has been reported to be the primary tick vector for F. tularensis, but the lone star tick (Amblyomma americanum) and other tick species also have been shown to harbor F. tularensis. This review highlights what is known, not known, and is debated, about the roles of different tick species as environmental reservoirs and transmission vectors for a variety of F. tularensis genotypes/strains.