Merlo was an indefatigable writer and traveler as she penned articles for her order and made visits across the world to communities that were established in nations such as the United States of America and Australia.

Pope John Paul II conferred the title of Venerable upon her in 1991 after confirming that she had lived a model life of heroic virtue.

[2] She received the sacrament of baptism on 22 February 1894 in the parish church of Saint John the Baptist from Father Pietro Palladino; her godparents were Leone Merlo and Margherita Rava Rolando.

[2] In 1916 she attended a series of spiritual exercises that Alberione oversaw and made her initial vows on 29 June 1916 – the Feast of Saints Peter and Paul.

She and other sisters assumed the habit for the first time on 30 October 1928 while she later travelled to Salerno on 5 November 1928 with a group of religious to set up a house of the order there.

Merlo made her perpetual profession on 19 March 1929 and later sent her first circular letter as Superior General to the communities of the congregation on 26 December 1929.

Some of her writings became available after the order's internal news source Eco di Casa Madre commenced its printing run on 1 January 1934.

In December 1935 – upon Alberione's advice – she issued rules that demanded mandatory periodical correspondence between sisters and their Superior General with a particular focus on Christmas and the feast of Saint Paul.

[1] Merlo made her first international travels on 26 March 1926 after departing Genoa on the ship "Augustus" for Brazil and Argentina, while returning to Rome on 27 August 1936; she relocated to the generalate on 11 November 1936.

She made another sojourn on 28 January 1937 after leaving on the steamship Rex to visit homes in New York City, returning to Rome on 6 March 1937.

Merlo and Alberione then departed on 3 April 1949 to visit communities in the US and Mexico and then to India, Japan and the Philippines and made their return to Rome on 14 June 1952.

[2] On 21 March 1952 she and Alberione visited the US and Canada and then to Mexico before heading to Chile, Brazil and Argentina; the pair returned to Rome on 14 June 1952.

On 24 January 1962 she departed for India, the Philippines, Taiwan, South Korea, Japan and Australia and made the return trip to the generalate in Rome on 19 May 1962.

But Merlo fell ill in March 1962 while in the Philippines which prompted Costantina Bignante to be sent from Rome to both take care of her and remain with her for the rest of the trip.

Merlo travelled to Rome on 7 July 1963 and on 22 August 1963 met Pope Paul VI on the occasion of his visit to the Regina Apostolorum hospital in Albano.

The formal introduction to the cause was issued on 25 February 1982 once the Congregation for the Causes of Saints approved and conferred the posthumous title of Servant of God upon the late religious.

This all culminated on 22 January 1991 once Pope John Paul II confirmed that she had lived a model Christian life of heroic virtue and thus named her Venerable.