Community-based prevention of epidemic Rocky Mountain spotted fever among minority populations in Sonora, Mexico, using a One Health approach.

BACKGROUND: Rocky Mountain spotted fever (RMSF) is a significant public health problem in Sonora, Mexico, resulting in thousands of cases and hundreds of deaths. Outbreaks of RMSF are perpetuated by heavy brown dog tick infestations in and around homes. During 2009-2015, there were 61 RMSF cases and 23 deaths in a single community of Sonora (Community A). METHODS: An integrated intervention was carried out from March-November 2016 aimed at reducing tick populations with long-acting acaricidal collars on dogs, environmental acaricides applied to peri-domestic areas and RMSF education. Tick levels were measured by inspection of community dogs to monitor efficacy of the intervention. A similar neighborhood (Community B) was selected for comparison and received standard care (acaricide treatment and education). RESULTS: The prevalence of tick-infested dogs in Community A declined from 32.5% to 8.8% (p<0.01). No new cases of RMSF were identified in this area during the subsequent 18 mo. By comparison, the percentage of tick-infested dogs in Community B decreased from 19% to 13.4% (p=0.36) and two cases were reported, including one death. CONCLUSIONS: Community-based interventions using an integrated approach to control brown dog ticks can diminish the morbidity and mortality attributable to RMSF.

Novel hydrophobic interaction chromatography matrix for specific isolation and simple elution of immunoglobulins (A, G, and M) from porcine serum.

A new, highly acetylated agarose matrix (HA-Sepharose) was synthesized and used as a hydrophobic interaction chromatography (HIC) medium to specifically isolate immunoglobulins (Igs) from porcine serum. Recovery of Igs was in a single step and under mild conditions. HA-Sepharose adsorption was studied in terms of salt, gel acetylation time, flow rate, and protein concentration on the loading buffer. At 0.5 M Na2SO4, control with unmodified Sepharose retained a small fraction (0.70 mg/mL of matrix) of serum albumin. On the contrary HA-Sepharose retained primary Igs (IgA, IgG, and 53% of IgM) as revealed by sodium dodecyl sulphate 10% polyacrylamide gel electrophoresis (SDS-PAGE), quantitative radial immunodiffusion and immunodetection. At a flow rate of 1 mL/min, the HA-Sepharose column capacity (3.9 mg/mL of matrix) was similar to the reported capacity for the commercial thiophilic T-gel. However, HA-Sepharose showed higher recovery of IgA and IgM than the T-gel in the same salt conditions, clearly an advantage in terms of immunoglobulin recovery strategies. Acetylation changed the matrix adsorption from albumin to immunoglobulins; thus, the highly acetylated gel rendered recoveries of Igs from unprocessed porcine serum practically free of albumin.

Isolation of human serum immunoglobulins with a new salt-promoted adsorbent.

In this work a highly acetylated-ethylenediamine-Novarose (HA-EDA-Novarose) gel was synthesized and used as a new agarose-based salt-promoted adsorption chromatography (SPAC) matrix to effectively isolate serum immunoglobulins without the need of denaturing conditions. Samples of human serum in 0.5 M Na2SO4, 10 mM 3-(N-morpholino)-propane-sulfonic acid (MOPS), pH 7.6 were applied to a chromatographic column packed with the SPAC gel. Immunoglobulins (Igs) with affinity for the HA-EDA ligands were specifically adsorbed to the matrix, non-bound serum proteins were readily removed by washing the column with the same feed solution buffer. Bound Igs were effectively and very gently eluted by simply removing the salt from the feed solution buffer. The elution buffer consisted thus of only 10 mM MOPS, at pH 7.6 and no salt. The salt-dependent adsorption capacity of this system was estimated to be 7.3 mg/ml with protein recovery of about 93%. Sodium dodecyl sulfate-polyacrylamide gel (SDS-PAGE) electrophoresis analysis, radial immunodiffusion and enzyme-linked immunosorbent assays showed that immunoglobulins G, M and A (IgG, IgM and IgA) were the main components present in the elution fraction. The new SPAC adsorbent was used to purify Igs from human serum and IgG and IgA from non-pure commercially available Igs preparations in a very gentle single step.