CRTBI - Extended Abstracts - Serological evidence of Lyme arthritis in Egypt

Z O O E C O . O R G

Serological evidence of Lyme arthritis in Egypt

Nilsson, Ingrid (1); El-Gohary, Ahmed (2); Al-Din Saad, Alaa (2); Ragheb, Mostafa (3); Mostafa, Ola (2); Ljungh, Åsa (1)

(1) Dept Infectious Diseases and Medical Microbiology, Univ Lund, Sweden;
(2) Dept Clin Pathology, Suez Canal Univ Hospital, Ismailia, Egypt
(3) Dept Tropical Medicine, Suez Canal Univ Hospital, Ismailia, Egypt

Email: ingrid.nilsson@mmb.lu.se

The Suez Canal area is a coastal area with high humidity. Many of the mammalian and avian tick-hosts inhabit or migrate through this region, e.g. millions of birds cross Egypt during their annual migration and may shed ticks that subsequently transmit Borrelia spp from other geographical regions where Lyme borreliosis (LB) is endemic. Ixodes ricinus ticks have been collected in Egypt (Anderson JF, 1991) but in Egypt, clinicians rarely consider LB/Lyme arthritis as a possible diagnosis.

Serum samples obtained from 175 patients with active arthritis, visiting the Suez Canal University Hospital of Ismailia and the Communicable Diseases Research and Training Center, Suez, were screened by an enzyme immuno assay (EIA) for IgG antibodies against Borrelia burgdorferi sensu stricto (type strain B31). According to results of clinical and chemical tests patients were defined either as classified or unclassified arthritic cases. Unclassified arthritic patients were those with no clinical diagnosis for three months or more and negative in tests for rheumatoid factor, antinuclear antibodies and anti-DNA antibodies.

Thirty of 175 sera showed increased antibody levels by the B31-EIA, 12 from the classified group and 18 from the unclassified arthritic cases. Sera positive in the B31-EIA were further analysed by immunoblot using proteins of three other Borrelia species. Nine sera were positive with antigens of B. afzelii (ACA I, Swedish strain), one serum positive by B garinii immunoblot (strain 20047, France) and two sera were positive by B burgdorferi sensu stricto (strain 2591, USA). In addition, sera were tested by EIA for antibodies to Yerinia enterocolitica and Salmonella enterica that also may induce post-infectious arthritis.

None of the sera were positive in more than one of the immunoblots. Of the 18 samples interpreted as immunoblot-negative, all had antibodies reacting with Borrelia antigens but fewer than required for a positive test. This may reflect antigenic variability between strains isolated in the US and Europe compared to those that might be prevalent in Egypt, or the prevalence of new Borrelia subspecies. In total, 28 of 30 patients showed antibody reactivity to the OspA and/or OspB proteins, which supports a tissue tropism and/or that these antigens may have an arthritogenic potential. This study shows that LB exists in Egypt, and that specific diagnosis of Borrelia spp should routinely be performed.