RAT BITE FEVER AND ENVIRONMENT

Close contact and increasing exposure to exotic or wild animals and in this context to rodents coupled with gradual urbanization has increased the frequency of zoonotic diseases such as RBF (Graves and Janda, 2001; van Nood and Peters, 2005; Dendle et al., 2006). Valverde et al. (2002) reported an unusual infection in two non-human primates byS. moniliformis.

Along withGiardia,Cryptosporidium,E. coli,S. typhi,S. paratyphiandCampylobacter,Streptobacillus moniliformiswas implicated in several public and private drinking water related outbreaks in England and Wales from 1910 to 1999 as reported by Nicholset al.(2009). These outbreaks were significantly correlated

opening up of water flow channels as the water table drops and direct contamination of groundwater; and c) dry soil surface encouraging run-off and formation of cracks that affect the soil’s filtration capability.

Excessive rainfall besides causing wash out and spread of rats’urine and fecal materials over extensive areas may also impact the drainage rat population through flooding. This aspect has not yet been studied, but it should be taken seriously as one of the rats’ main dwelling-places is sewer system. Countries subjected to continuous floods are at high risk, especially in densely populated areas at low economic levels. With regard to climatic conditions, Lima et al. (2008), using a logistic model reported on the impact of summer precipitation on two closely related kangaroo-rat populations (Dipodomys merriami and Dipodomys ordii). It was hypothesized that increased summer precipitations intensify green vegetation needed for the reproduction of these rodents (specifically, females that require the water content of green vegetation for lactation).

Rat bite fever association with excessive rain fall was reported in a large outbreak caused by S.

moniliformis(304 people out of 700, 34%) in a boarding school in the UK (McEvoyet al., 1987). Water (from taps) and milk were first suspected to be the transmission vectors; however following an extensive epidemiological survey, the authors deduced that water from a nearby spring was the outbreak’s main pathogen reservoir. The assumption that this spring was infested with rats or even carrying a rat carcass could not be ruled out, as the water main (not connected to the spring) in this location did not cause additional cases outside the school. In this special case, digging around the building and exceptionally stormy weather had been reported, both events suspected of causing disorder of the local rat population resulting in accidental contact with spring water.

Finally, petrochemical land waste treatment was shown to induce cotton rats’dental lesions through fluorosis (Raffertyet al., 2000). This observation is important as such lesions can increase the potential rat bite fever pathogens being transmitted between these rodents as well to other animals including humans with which they may come in contact.

2.18.2 REFERENCES

Andre, J.M., Freydiere, A.M., Benito, Y., Rousson, A., Lansiaux, S., Kodjo, A.et al.(2005) Rat bite fever caused by Streptobacillus moniliformisin a child: human infection and rat carriage diagnosed by PCR.J. Clin. Pathol.58, 1215–1216.

Anonymous (2005) Fatal rat-bite fever–Florida and Washington, 2003.MMWR Morb Mortal Wkly Rep53, 1198–1202.

Cunningham, B.B., Paller, A.S. & Katz, B.Z. (1998) Rat bite fever in a pet lover.J. Am. Acad. Dermatol.38, 330–332.

Dendle, C., Woolley, I.J. & Korman, T.M. (2006) Rat-bite fever septic arthritis: illustrative case and literature review.

Eur J Clin Microbiol Infect Dis25, 791–797.

Gaastra, W., Boot, R., Ho, H.T.K. & Lipman, L.J.A. (2009) Rat bite fever.Vet. Microbiol.133, 211–228.

Graves, M.H. & Janda, J.M. (2001) Rat-bite fever (Streptobacillus moniliformis): a potential emerging disease.Int J Infect Dis5, 151–154.

Lima, M., Ernest, S.K.M., Brown, J.H., Belgrano, A. & Stenseth, N.C. (2008) Chihuahuan desert kangaroo rats:

nonlinear effects of population dynamics, competition, and rainfall.Ecology89, 2594–2603.

McEvoy, M.B., Noah, N.D. & Pilsworth, R. (1987) Outbreak of fever caused byStreptobacillus moniliformis.Lancet 12, 1361–1363.

Nichols, G., Lane, C., Asgari, N., Verlander, N.Q. & Charlett, A. (2009) Rainfall and outbreaks of drinking water related disease and in England and Wales.J Water Health.7, 1–8.

Rafferty, D.P., Lochmiller, R.L., Kim, S., Qualls, C.W., Schroder, J. et al. (2000) Fluorosis risks to resident hispid cotton rats on land treatment facilities for petrochemical wastes.J. Wildl. Dis.36, 636–645.

Torres, L., Lòpez, A.I., Escobar, S., Marne, C. Marco, M.L.et al.(2003) Bacteremia byStreptobacillus moniliformis:

first case described in Spain.Eur J Clin Microbiol Infect Dis22, 258–260.

Rat bite Fever (RBF) or Sodoku 117

Valverde, C.R., Lowenstine, L.J., Young, C.E., Tarara, R.P. & Roberts, J.A. (2002) Spontaneous rat bite fever in non-human primates: a review of two cases.J Med Primatol31, 345–349.

van Nood, E. & Peters, S.H.A. (2005) Rat-bite fever.The Neth J Med63, 319–321.

Environmental Aspects of Zoonotic Diseases 118

Chapter 2.19 Rickettsioses

[RICKETTSIASPP.]

The genus Rickettsia are gram-negative, non-spore forming, non-motile, highly pleomorphic bacteria (cocci, rods or thread-like). All species are obligate intracellular parasites that replicate within cytoplasm of eukaryotic cells as host (mainly endothelial cells). The main species are: Rickettsia rickettsii, Rickettsia felis, Rickettsia prowazekii, Rickettsia typhi, Rickettsia conorii, Rickettsia africae and Rickettsia akari.Different ticks, fleas, and lice are the vectors of this pathogen and mammals (including humans) are the host. There are several diseases caused by Rickettsia such as typhus, scrub typhus (tsutsugamushi fever) rickettsialpox, Rocky Mountain spotted fever, Mediterranean spotted fever (Boutonneuse fever), African tick bite fever, Queensland tick typhus, Australian Tick Typhus and Flinders Island Spotted Fever. Rickettsioses can occur sporadically, endemically but also epidemically (e.g., typhus, Q fever) (Salgo et al., 1988) (Table 2.19.1). Rickettsia has also been associated with a range of plant diseases and as an arthropods’endosymbiont. Resembling viruses, they grow exclusivelly inside living cells. The name rickettsia is often used for any member of the Rickettsiales. They are thought to be the closest living relatives to bacteria that evolutionarily are thought to be the origin of the mitochondria organelle present inside most eukaryotic cells. Diseases caused by the genusRickettsiawill manifest themselves according to the infecting agent’s tropism such as: skin-texanthemas and necroses;

lung-pneumonia; heart-myocarditis; brain-meningoencephalitis; gastrointestinal tract-diarrehea; pancreas-pancreatitis; liver-hepatitis; blood- thrombocytopenia and hemorrhages and kidney-hypoperfusion and acute renal failure.