Containing a measles outbreak in Minnesota, 2017: methods and challenges

AIMS

We report on a measles outbreak largely occurring in Minnesota's under-vaccinated Somali community in the spring of 2017. The outbreak was already into its third generation when the first two cases were confirmed, and rapid public health actions were needed. The aim of our response was to quickly end transmission and contain the outbreak.

METHODS

The state public health department performed laboratory testing on suspect cases and activated an Incident Command staffed by subject matter experts that was operational within 2 h of case confirmation. Epidemiologic interviews identified exposures in settings where risk of transmission was high, that is, healthcare, childcare, and school settings. Vaccination status of exposed persons was assessed, and postexposure prophylaxis (PEP) was offered, if applicable. Exposed persons who did not receive PEP were excluded from childcare centers or schools for 21 days. An accelerated statewide measles, mumps, and rubella (MMR) recommendation was made for Somali Minnesota children and children in affected outbreak counties. Partnerships with the Somali Minnesota community were deepened, building off outreach work done with the community since 2008.

RESULTS

Public health identified 75 measles cases from 30 March to 25 August 2017: 43% were female, 81% Somali Minnesotan, 91% unvaccinated, and 28% hospitalized. The median age of cases was 2 years (range: 3 months-57 years). Most transmission (78%) occurred in childcare centers and households. A secondary attack rate of 91% was calculated for unvaccinated household contacts. Over 51,000 doses of MMR were administered during the outbreak above expected baseline. At least 8490 individuals were exposed to measles; 155 individuals received PEP; and over 500 persons were excluded from childcare and school. State and key public health partners spent an estimated $2.3 million on response.

CONCLUSION

This outbreak demonstrates the necessity of immediate, targeted disease control actions and strong public health, healthcare, and community partnerships to end a measles outbreak.

Identification of a mutation associated with erythromycin resistance in Bordetella pertussis: implications for surveillance of antimicrobial resistance

Erythromycin treatment failures and in vitro resistance of Bordetella pertussis have been reported on several occasions in the past few years, but the mechanism of resistance has not been described. One potential mechanism, genetic modification of the erythromycin-binding site on the 23S rRNA of the 50S ribosomal subunit, has been observed in other bacteria. To explore this possibility, we amplified the portion of the 23S rRNA gene encoding the central loop of domain V. DNA sequencing and restriction fragment length polymorphism of the PCR products showed that each of the four erythromycin-resistant B. pertussis strains tested contained an A-to-G transition mutation at position 2058 (Escherichia coli numbering) of the 23S rRNA gene. The mutation was not found in seven erythromycin-susceptible isolates tested. Two of the resistant isolates were heterozygous, containing at least one mutant copy and one wild-type copy of the 23S rRNA gene. These results indicate that erythromycin resistance in these strains is likely due to a mutation of the erythromycin-binding site in the 23S rRNA gene. Identification of the resistance mechanism will facilitate development of molecular susceptibility testing methods that can be used directly on clinical specimens in the absence of an isolate.

Antineoplastic activity of esters and amides of N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl]-aminoacids

The antineoplastic activity of 7 ester derivatives and 15 amide derivatives of N-[N'-(2-chloroethyl)-N'-nitrosocarbamoyl (CNC)]-aminoacids was examined in transplanted rat leukemia L 5222. All esters except the ethylester of CNC-L-isoleucine showed only a moderate antitumor activity. CNC-L-isoleucine ethylester effected some cures and showed the lowest toxicity of this series of compounds. The amide derivatives on the other hand were highly active in L 5222; all compounds effected cures in the dose range investigated.