Thanks ever so much. I believe you are right. This matches perfectly with my ancestor looking for gold in California.
Definition: Chagres fever [chag′ris]
Etymology: Chagres River, Panama; L, febris
A phlebotomus arbovirus infection transmitted to humans through the bite of a sandfly. The disease is rarely fatal and is characterized by fever, headache, and muscle pains of the chest or abdomen. There may be nausea and vomiting, giddiness, weakness, photophobia, and pain on moving the eyes. The infection usually subsides within a week. Supportive treatment includes analgesics, bed rest, and adequate fluid intake. The disease is most common in Central America. Also called Panama fever.
(Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.)
And the connection to California gold seekers:
(American Journal of the Medical Sciences: April 1856 – Volume 62 – Issue – ppg 319-325; Chagres Fever, page 319; found in Google search.)
“ART. II. - On “Chagres Fever” and some of the other Diseases to which California Emigrants are liable. By Wm. P. Buel, M.D. Surgeon Pacific Mail Company.
Of the vast multitudes who, since the years 1847 and 1848, have found their way from the older States of the confederacy to the shores of the Pacific, by far the largest portion has passed by the Isthmus of Panama. The remainder, which made the transit by the Nicaragua route, have been subjected to substantially the same class of diseases. Lying a few degrees further north, but still within the tropics, the sources of disease on the two routes cannot essentially differ. My personal observations and experience have been confined to the Panama route, and to that alone will my remarks immediately apply. With regard to the two other methods of reaching the Pacific – the one by a protracted sea voyage, and the other by a long and perilous land journey across the Rocky Mountains and the sandy deserts which lie at their base – the mortality, which, from disease, has been comparatively trifling, though by other perils, both by land and sea, it has been considerable, does not obviously form a part of the present discussion.
Large bodies of persons, mostly from northern and temperate climates, unaccustomed, for the most part, to the excitement and vicissitudes of travel, lured by the golden rumors which reached them on every breeze, have been tempted to a sudden and violent disruption of those ties which bind men generally to the locality or neighbourhood of their birth. After a preliminary journey of hundreds, perhaps thousands of miles, to their port of embarkation, they find themselves huddled into crowded ships, and are, in a few days, transferred into the bosom of the tropics. The Atlantic portion of the journey terminated, another brief space finds them set ashore upon the Isthmus of Panama.
To cross that “narrow neck of land” was, until quite recently, especially during the rainy season, a perilous and toilsome enterprise. The emigrant was exposed by day alternately to drenching rains and to the scorching beams of a vertical sun; at night, to damp and sickly exhalations. He had little protection from the weather, and often was obliged to camp out, to sleep on the ground in the open air. Add to these, bad diet, indulgence in tropical fruits, and the liberal use of intoxicating liquors, always bad, and he could hardly be expected to escape disease. The wonder is, not that multitudes perished, but rather that any escaped. …”