Lyme disease

Case report: A patient coinfected by Borrelia burgdorferi sensu lato and spotted fever group Rickettsiae in Urumqi, China

RATIONALE

Both Borrelia burgdorferi sensu lato and spotted fever group Rickettsiae (SFGR) are pathogens carried by ticks. There is a possibility of co-infection with these tick-borne diseases.

PATIENT CONCERNS

Male patient, 63 years-of-age, admitted to hospital with skin rash presenting for 1 week and fever with cough and expectoration for 3 days before admission.

DIAGNOSES

We diagnosed that the patient was co-infected by B burgdorferi sl and SFGR using laboratory test results and the patient's clinical manifestations.

INTERVENTIONS

The patient started therapy with oral minocycline, then levofloxacin by intravenous injection for SFGR. Meanwhile, he was treated with penicillin G sodium, cefoperazone sulbactam sodium and ceftriaxone by intravenous injection for B burgdorferi sl.

OUTCOMES

After the patient was in stable condition, he was discharged from hospital.

LESSONS

This case report highlights the possibility of co-infection by 2 tick-borne diseases in Urumqi, Xinjiang Uygur Autonomous Region, China. The antibiotic therapy should be based on the detection of pathogenic bacteria, and the different susceptibilities of co-infecting bacteria should be considered.

A field survey on parasites and antibodies against selected pathogens in owned dogs in Lilongwe, Malawi

The aim of this study was to screen for selected parasites and antibody levels against vectorborne pathogens in owned dogs in Lilongwe, Malawi. The study population consisted of 100 dogs; 80 participating in vaccination-spaying campaigns and 20 visiting a veterinary clinic as paying clients. All dogs went through a general physical examination including visual examination for signs of ectoparasites. A total of 100 blood samples were analysed using commercial snap tests and 40 faecal samples by egg flotation in saturated sodium chloride. The sampled dogs had a seroprevalence of 12% for Anaplasma spp., 22% for Ehrlichia spp., 4% for Dirofilaria immitis and 1% for Leishmania spp. Eggs from Ancylostoma spp. were found in 80% of the faecal samples, whereas eggs of Trichuris vulpis, Toxocara canis and Toxascaris leonina were only present in 3%, 8% and 13% of the samples, respectively. Ectoparasites such as Ctenocephalides sp., Trichodectes sp. and ticks were present on 98%, 25% and 11%, respectively, of the campaign dogs. Among client dogs, 35% had Ctenocephalides fleas, 10% had Trichodectes lice and none had ticks. Public education and prophylactic treatment could be used to improve the animal welfare of dogs; this would most likely also have positive impact on public health.

Identification of two genes essential for sperm development in the male tick Amblyomma hebraeum Koch (Acari: Ixodidae)

In most ticks of the family Ixodidae, gonad maturation and spermatogenesis are stimulated by the taking of a blood meal. Previous work from this laboratory identified 35 genes that are up-regulated by feeding [Weiss, B.L., Stepczynski, J.M., Wong, P., Kaufman, W.R., 2002. Identification and characterization of genes differentially expressed in the testis/vas deferens of the fed male tick, Amblyomma hebraeum. Insect Biochemistry and Molecular Biology 32, 785-793]. The functions of most of these genes remain unknown. We used RNA interference technology to investigate the consequences of blocking the function of 13 of these genes. Attenuation of the expression of two of these in particular, AhT/VD 8 and AhT/VD 10, correlated with deformities in the testis and abnormalities in spermiogenesis. Furthermore, most females fed in the company of these males did not engorge properly and laid many fewer eggs, most of which were infertile.

Histopathological Studies of Experimental Lyme Disease in the Dog

Experimental borrelia infection was induced in 62 specific--pathogen-free beagle dogs by exposure to Ixodes scapularis ticks harbouring the spirochaete Borrelia burgdorferi. Clinical signs of Lyme disease occurred in 39/62 dogs, the remaining 23 being subclinically infected. Clinical signs consisted of one to six episodes of transitory lameness with joint swelling and pain, most commonly affecting the elbow or shoulder joints. The polymerase chain reaction and culture demonstrated that the dogs remained infected for up to 581 days. At necropsy, gross findings consisted of lymphadenopathy in the area of tick attachment. Microscopical changes consisted of effusive fibrinosuppurative inflammation or nonsuppurative inflammation, or both, affecting synovial membranes, joint capsules and associated tendon sheaths. Plasma cells dominated areas of chronic inflammation, with CD3(+) T cells being present in lesser numbers. Microscopical signs of arthritis were polyarticular and more widespread than indicated by clinical signs, and most of the subclinically affected animals also had synovitis. In areas of tick attachment to the skin, hyperkeratosis and a mixture of suppurative and nonsuppurative dermatitis were encountered. Lymphadenopathy in superficial lymph nodes resulted from follicular and parafollicular hyperplasia. In 14/62 dogs, lymphoplasmacytic periarteritis and perineuritis were noted, resembling lesions found in human Lyme disease and syphilis, in which an underlying microangiopathy has been proposed.

The shifting landscape of tick-borne zoonoses: tick-borne encephalitis and Lyme borreliosis in Europe

The two major vector-borne diseases of northern temperate regions, tick-borne encephalitis (TBE) and Lyme borreliosis (LB), show very different epidemiological patterns, but both have increased significantly in incidence since the 1980s. Insight into the temporal dynamics of TBE, gained from statistical analysis of spatial patterns integrated with biological explanation, suggests that the recent increases in TBE cases in Central Europe and the Baltic States may have arisen largely from changes in human behaviour that have brought more people into contact with infected ticks. Under forecast climate change scenarios, it is predicted that enzootic cycles of TBE virus may not survive along the southern edge of their present range, e.g. in Slovenia, Croatia and Hungary, where case numbers are indeed decreasing. New foci, however, are predicted and have been observed in Scandinavia. At the same time, human impact on the landscape, increasing both the habitat and wildlife hosts of ticks, has allowed tick populations to multiply significantly. This probably accounts for a genuine emergence of LB, with its high potential transmission rate, in both the USA and Europe, although the rate of emergence has been exaggerated by improved surveillance and diagnosis.