Tularemia in Range Sheep: An Overlooked Syndrome?

Abstract

Abstract. Abortion and death caused by Francisella tularensis were well recognized in range flocks of domestic sheep in Idaho, Montana, and Wyoming in the first 6 decades of the 20th century. The current report describes 4 episodes of tularemia in 3 range flocks in Wyoming and South Dakota in 1997 and (1 flock was affected twice). Flock owners reported that ticks were unusually numerous and commonly present on sheep during outbreaks. Tularemia presented as late-term abortions (3 episodes) or listlessness and death in lambs and, to a lesser extent, ewes (1 episode). Lesions were multifocal pinpoint necrotic foci in tissues, particularly spleen, liver, and lung. An immunohistochemical procedure demonstrated F. tularensis, particularly in necrotic foci. The diagnosis was corroborated by bacterial isolation and, in individual cases, by serology, fluorescent antibody assay, and/or polymerase chain reaction detection of F. tularensis. Diagnosticians in endemic areas should include tularemia as a differential diagnosis when investigating lateterm abortions or outbreaks of fatal illness in young lambs, particularly in years of high tick activity and when characteristic necrotic foci occur in spleen, liver, and lung.

Transovarial Transmission ofFrancisella-Like Endosymbionts andAnaplasma phagocytophilumVariants inDermacentor albipictus(Acari: Ixodidae)

“…New or expanded pathogen transmission cycles that involve tick-borne bacteria are believed to arise because of natural and human-driven environmental forces such as climate change, land development, and livestock shipment that alter habitat, vector, and host interactions (Telford and Goethert 2004, Harrus and Baneth 2005, Parola et al 2005, Jones et al 2008). That paradigm is consistent with the increasing prevalence in the United States of human granulocytic anaplasmosis, Lyme disease, and tularemia in concert with expanding populations of deer and ticks (Madhav et al 2004, Rand et al 2004, Piesman and Gern 2004, Eisen 2007, Paddock and Yabsley 2007, O’Toole et al 2008). …”

“…Although later studies further implicated D. andersoni and other ticks as vectors of F. tularensis , the complex epidemiology of tularemia in North America has changed over the past century and involves rabbits, terrestrial rodents, aquatic mammals, lice, blood-feeding flies, and fomites in addition to ticks (Hayes 2005). At present, transmission by Amblyomma americanum and Dermacentor variabilis ticks is suspected as the main cause of human tularemia in the United States and by D. andersoni in recent livestock outbreaks (Eisen 2007, O’Toole et al 2008, Petersen et al 2009). The first described FLE, “DAS,” was also found in D. andersoni and was pathogenic when injected into guinea pigs or hamsters (Burgdorfer et al 1973) but was not present in tick salivary glands and was not tick transmissible to guinea pigs in the laboratory (Niebylski et al 1997).…”

Treatment of Tularemia in Pregnant Woman, France

“…Severe illness or death caused by infection with F. tularensis could be a risk for a pregnant woman or her fetus; the role of F. tularensis as an agent of abortion and intrauterine death is well recognized in sheep ( 10 ) but not in pregnant women. A major difficulty in this instance was the choice of the antimicrobial drug regimen, because first-line antibiotics currently recommended for treatment of tularemia, including the aminoglycoside gentamicin, fluoroquinolones, and tetracyclines ( 1 , 2 , 7 , 8 ), may be toxic for pregnant women or fetuses.…”

Investigation on Tularemia in potential reservoirs’ of Anatolia

“…Of the 401 sera, 156 (38.9%) had antibody titers between 1/10 and 1/640 while 111 (27.6%) exhibited 1/20 antibody titer which were also accepted as indicative of tularemia. O'Toole et al (10) studied the existence of F. tularensis in 3 different local herds of sheep between 1997 and 2007. The report describes 4 periods of tularemia in these herds.…”