Lou Marchetti

Title: The Nurse and the Pirate
Author: Peggy Gaddis
Publisher: Ace D-536
Published: ©1961
Illustrator: Lou Marchetti
Review available

He is not credited, but this is very much in his style. 

After five months as a cruise nurse on the luxury liner Santa Theresa, Kathy was glad that the trip was almost over and that she soon would be back to the demanding atmosphere of a big city hospital. Suddenly, during a starless tropical night, a desperate band of men seized the liner by force and terrorized the passengers and crew. All at once Kathy not only had more nursing to do than any one nurse could handle, but she had become the special object of attention of the leader of the pirates!

Robert Maguire

Title: Ship's Nurse
Author: Rosie M. Banks
Publisher: Permabooks M-4223
Published: January 1962, ©1962
Illustrator: Robert Maguire
Review available

This is not credited, but it is in his style.

When her aunt, the ship’s senior nurse, breaks her ankle, Cathy volunteers for duty. There seems to be more than the usual shipboard intrigue—the ship’s doctor drinks tea, secretly laced with rum, to forget painful memories. His young assistant yearns to leave the ship to start his own practice. A stowaway—on a last fling before settling down to responsibility—is discovered. A raucous Texas dowager drinks too much and her gigolo-husband has a roving eye. Cathy herself if faced with an oversupply of admirers. An innocent flirtation and sudden tragedy make Cathy realize the depth of her dedication to nursing—and where her heart is.

Lou Marchetti

Title: Nurse at the Castle
Author: Joanne Holden
Publisher: Magnum Books
Published: ©1965
Illustrator: Lou Marchetti
Review available

This is uncredited, but it is very much in his style.

It was surprising how much courage it took to walk into the bedroom of someone who has tried to choke you, Nancy thought. But she need not have worried. Lavinia Barclay was her usual friendly self and greeted Nancy cheerily. “Good morning. And to what do I owe the pleasure of this early morning visit from the doctor?” Nancy answered evasively. “I think he was invited to sleep over. That’s all.” She changed the subject. “Did you sleep well?” “Beautifully,” her patient answered. Evidentally [sic] Lavinia Barclay had no notion of what had happened the night before. And, to Nancy, this was the most frightening thing of all…

Gilbert Riswold

Title: Redheaded Nurse
Author: Bennie C. Hall
Publisher: Dell
Published: April 1961, ©1960
Illustrator: Gilbert Riswold
Review available.

He is credited on the back cover.

Jane Hamilton stood on the top deck of the cruise ship Madrigal, watching the twinkling lights that marked the Mediterranean shoreline. It was midnight, and the sound of laughter and music floated up from the Carnival Room on the deck below. She had known so few carefree hours in her young life, and now she longed to become a part of the gaiety surrounding her—but as ship’s nurse, she was here to work, not to enjoy herself. It would be so easy, she thought, to set conscience aside and forget her job—to surrender completely to a world where anything might happen…

Rudy Nappi

Title: Police Nurse
Author: William Neubauer
Publisher: Macfadden
Published: 1965, ©1964
Illustrator: Rudy Nappi
Review available

This is not credited, but is done in his style.

They warned her—you’re asking for trouble! But Nurse Elaine wouldn’t give up. As a police nurse it was her job to help people, and Ed Morley, accused of murder, needed her help. His youth, good looks, and wealth had turned the whole town against him. Elaine was sure he wouldn’t get a fair trial unless Lydia Shelton helped. Lydia was the owner of the town’s paper—and Elaine’s rival for reporter Mike Jones’ heart. And Lydia promised to help, but her price was high—Nurse Elaine must leave town and never see Mike Jones again.

Lou Marchetti

Title: Nurse Missing

Author: Elizabeth Kellier
Publisher: Ace
Published: ©1961
Illustrator: Lou Marchetti
Review available

He is not credited, but this is very much in his style.

When Anne Leatherington, a young R.N., accepted a private case at Craigash, an isolated ancient estate in the Scottish Highlands, she found herself confronted by one mystery after another. Suddenly, a torrent of questions overwhelmed her as she became a victim of her own curiosity. Why was her patient, the seemingly harmless, senile Mrs. McGray, terrified of her own stepson, Charles, the brooding owner of Craigash? And why was his past such a grim secret? But the darkest mystery of all was what had become of Anne’s predecessor, the previous nurse who had disappeared in curious circumstances. As Anne glimpsed the terrifying answers she would realize that the truth could destroy her and the man she had come to love.